Laguna Seca: where summer meets winter (1/3)

Intro: lack of oxygen, excess of radiation

Bolivia is entirely situated in the tropical belt, but due to the huge differences in elevation has a diverse and complex climate. While the eastern part is dominated by wet lowlands and savannas, the western sector is mostly a high and dry plateau named the Altiplano. With an average elevation of around 3800 meters, this barren highland which is shared with three other South-American countries (Peru, Chile and Argentina) is the second largest and elevated in the world after the Tibetan Plateau, concomitantly the air contains only about 60% of the oxygen found at sea level.

The driest part is represented by the westernmost stretch, which gradually descends into the hyper-arid Atacama desert towards the coast of the Pacific Ocean. In Bolivia it can be found in the south-western corner of the country. In the middle of this region there is an extensive flat area covered with thick salt crust named Salar de Uyuni, which represents the closed bottom of the highland’s interior. As such, it has no outlet and all the rivers (mostly intermittent) are collected by the huge, shallow bowl where the water rapidly evaporates in the thin and dry air.

With more than 10.000 square km surface area, Salar de Uyuni (3660 m) is the largest salt flat in the world

The climate of the plateau is extreme. Especially notable are the daily temperature fluctuations, which can exceed 30 degrees in the dry season, which has its peak in the south hemisphere’s winter months (June-August). Beside the huge thermal amplitudes the other peculiar weather aspects are the strong westerly winds and the intense UV radiation. Regarding the latter, the highest value ever recorded on the surface of the Earth – an incredible 43.3! – was measured on the peak of Licancabur volcano (5916 m) situated right on the border between Bolivia and Chile on the fringes of the Atacama. Just imagine that the level 11 is considered “extremely high” on the UV chart and most European countries never reach that even in the summer.

Choosing the target

While already knowing that the Altiplano likely provides the best general context regarding the biggest daily temperature fluctuations, I was of course interested in the “finer details” which can maximalise this potential. Regarding the timing I concluded that the best period must be somewhere near the equinox, when the heating and cooling has similar chances of manifestation. As with both very short nights (think of polar summers) or very short daylight (think of polar winters) the thermal amplitudes are pretty small (constantly cool or constantly frigid), the biggest ones have to be equally far from both.

The location of the research area (black dot) inside the Altiplano (gray spectrum)

Concomitantly, much better is to have an abrupt sun-path, where the irradiance reaches the highest possible angle at zenit (namely tropical latitudes). This is of course influenced also by other factors such as the distribution of moisture (clouds and precipitation) between the seasons.

Taken all into account the month of September stood out as according to the available climatological statistics (Uyuni in Bolivia, Calama and San Pedro de Atacama in Chile) in the south-western part of the Altiplano it is the same dry as the mid-winter period, receiving almost no precipitations. Now let’s move to the topographical aspects.

Topo-map with the unnamed depression (lower-right center) situated east of the Alota – Villamar Mallcu dirt road

As the thinner air has less heat-retaining capacity, the general rule to follow is: the higher the better. In the simplified version the limitation is given by the highest possible elevation where closed basins can be found as in those places the colder air can be gravitationally collected. But there are also other influencing elements like the wind pattern, which instead is inversely proportional with the targeted amplitude potential, making the real picture more complex. Best should be (especially for shorter term observations like mine) to make a wise compromise, founding the “golden mean” between elevation and stability.

As such, I concluded that around 4000 meters elevation must be a well grounded decision, sufficiently high to have a serious advantage compared to the low elevations, but still relatively stable compared to the protruding tall ridges and peaks where the wind is certainly more active.

Satellite view of the endorheic basin with the contour levels 30, 20, 10 and 5 meters marked with red

Meticulously scanning the map I found out that there are only a few closed basins with sufficient depth which doesn’t have lakes on their bottom and of course exactly these are the best for my purpose. Finally I’ve chosen an unnamed depression south of Villa Alota settlement, whose floor is situated around 4030 meters, while the outflow point is some 30 meters higher. The bottom looks completely dry, lacking even the characteristic white salt crust.

Brief summary of the research

The Bolivian journey started on 13th September, landing in Santa Cruz de la Sierra, the biggest city of the country. Continuing with an internal flight to Sucre, the next day I reached an intermediate elevation between the hot lowlands and the arid high plateau. After two other days of acclimatization I arrived in Uyuni on 16th by bus via Potosí. On 17th I traveled to Villa Alota with a previously hired private jeep to begin the research as soon as possible, approaching the chosen spot a little more on the dirt track towards Villamar Mallcu. I started the hike with the equipment around 1 PM.

View of Laguna Seca from the west

After around 1.5 hours I reached the bottom of the nameless endorheic basin where the instruments were mounted on the tripod, which was also stabilized with an attached bag filled with rocks. The coordinates are 21.498 S, 67.547 W, the elevation around 4030 m and the distance of the sensor from the ground is 170-180 cm. The weather station started its operation at 2:56 PM. First reading: 14.4 degrees Celsius.

I did not waited long here, but returned from Alota the next day to spend the following two nights near the equipment. In all three cases the temperature dropped below -15 degrees, the coldest being the third morning with -16.5 degrees Celsius. The sky was generally clear with some altocumulus invasions during the evening and the first part of the second night. The wind pattern has a pretty obvious course, the afternoons being dominated by strong westerlies, while the nights and mornings are much calmer. I left the research spot in the morning of 20th and spent the following days in and around Uyuni.

The weather station on the bottom of the basin

After six days I returned to the endorheic basin for one last night after which the equipment was collected. That morning (27th) was the coldest of the entire research (-19.0 degrees Celsius at 6:23 AM) and it was also the period when the biggest thermal excursion happened: 38.1 degrees in under 24 hours, starting the huge drop from the previous day’s positive 19.1 degrees.

Six out of ten days the temperature fluctuation exceeded 30 degrees (dropping every time below -10) with a very likely seventh (the day before the last) when the strong afternoon wind overturned the tripod disconnecting the sensor. The middle days were somewhat milder, when at times I observed partly covered sky in the Uyuni area.

The coldest morning of the research was the last one

During my solitary hikes I saw many llamas on the outer slopes of the basin, where the locals have started the spring work on the quinoa fields and only vinunas inside, on the bottom. I spotted also some eagles, a viscacha and observed Darwin’s rhea (suri) tracks in the sand. Near my camp which was situated a little higher on the northern slope I identified signs of smaller scale mining activity. Except the relatively busy dirt track where the tourist filled 4wd cars circulated the surroundings lacked human presence, meeting only once two llama herders on the periphery of the basin.

The instruments used in the field

-One LogTag UTRED30-16 data logger with the measuring range between -40 and +99 degrees Celsius, an accuracy of 0.5 degrees Celsius and a resolution of 0.1 degrees Celsius

-One Greisinger G1710 thermometer with the measuring range between -70 and +250 degrees Celsius, an accuracy and resolution of 0.1 degrees, used for instant hand measurements

-One photo camera tripod serving as the support for the instruments

-One helical solar radiation shield from Barani Design Technologies: https://www.baranidesign.com/

The Barani Pro shield fighting against the vicious UV radiation

To be continued…

Laguna Seca: where summer meets winter (2/3)

Journey photo album

Catedral Metropolitana Basílica de San Lorenzo, Santa Cruz de la Sierra: My plane landed at Viru-Viru airport on 13th September where hot wind (around 36 C) and haze greeted me. Feels also pretty humid. Not the weather I came for, but certainly an interesting debut.
The city has a rapid pace, maybe too rapid for my taste. You must be careful with the traffic, the drivers does not have much patience here. At the central square is better. During the night the weather changed, cooling down significantly (around 20 C) because of the torrential rain. Only the wind remained there from the old equation. Back to Viru-Viru, as I have local flight to Sucre.
Big festivity in Sucre: With some delay the plane landed at Alcantari aiport (3100 m elevation), around 30 km from the city (2800 m). Taxis are not expensive here. While Santa Cruz (400 m elevation) has some dodgy neighborhoods and can be challenging during the night (I didn’t tried out), Sucre feels much more safe and is also cleaner. Let’s forget about the mess after the mega-party, it was rapidly cleaned the next morning. Not my head which was heavily strucked by “soroche” (altitude sickness) because of the rapid change from near sea-level. It was kind of surprising, never felt ill at this elevation until now.
At “Jesus’s heart” monument the next day: Around noon my condition improved, so went out to do some mild cardio workout. This hilltop (300 meter elevation gain) was a good choice to check the gears. The communal cohesion is evident in the city, which is known as the second capital of Bolivia. Locals may say it’s the real one.
Also known as “the white city”, with its general colonial aspect, Sucre has a positive and tranquil vibe
Yes, those are palm trees at 2800 meters. The climate here is one of the best in the country, which can be summarized as a constant spring. Not hot, not cold, not too rainy, not too arid. But don’t underestimate the UV radiation, which isn’t modest.
Potosí historical center: Reaching the heights of the Altiplano (almost 4000 meters) the next evening by bus, I felt in my elements both physically and emotionally. The soroche didn’t returned. I’ve read before that the body’s reaction to the high elevations are pretty unpredictable, now I experienced it live again.
Similar in its colonial aspect with Sucre, Potosí is dominated by pastel colors (especially pinkish), which gives him a more ancient general look. While Sucre can be considered the heart of national identity, here is the center of the spanish heritage. Pleasant cool morning, around positive 5 degrees between the old walls.
Statue of liberty: nice hyperboloid shape by the way
Yeah, definitely has a soul, I think it’s my favorite bolivian city
View from a tower towards Cerro Rico (4780 m), the famous mountain which had the biggest silver mines in the world in the 16-18. centuries, strongly contributing to the rapid ascent in power of the Spanish Empire. Still a lot of inner richness there in our days. Well, take this literally, the actual story behind the exploitation is less appealing from a humanistic perspective.
Villa Alota: After another 4 hour bus journey to Uyuni, only slept there once as I felt rushed by the good weather conditions to start the research as soon as possible. Having a previous arrangement in this regard to hire a private jeep, we reached the very basic looking settlement on the new paved road before noon. It was windy as it can be, what a start!
Flamingoes in the wetlands (bofedales): I decided to stay 3 days in the area, spending the latter 2 in the wilderness, while in this first one I will sleep in Alota after placing the measuring equipment. The forecast shows the best conditions for the second and third night, that’s why.
Henry, the driver with a lonely altocumulus lenticularis above: Continuing on the dirt track in the direction of Villamar Mallcu around 15 km, we approached the chosen place more and before 1 PM I started the hike
Above 4000 meters elevation: O yeah, I was waiting for this from a long time. Too bad, my GPS died right at the starting spot (could be the dust or just bad timing?) Anyhow I have everything crucial in my memory, let’s get into it.
First view of the endorheic basin: It seems that I guessed the directions right, the edge of the depression wasn’t too far. The weather is still windy, though less than in Alota where was on the border of violent. The temperature is moderate. Unsurprisingly, nobody in the entire area.
Reaching the bottom around 2:30 PM, I mounted the instruments on the tripod, secured it with an attached bag (actually the tripod’s own) filled with rocks collected near the slope and shortly before 3 PM the logger was started: 14.4 degrees Celsius, must be around the hottest time of the day. The wind persisted.
First milestone, happy with the installation
Even flatter than I thought, the bottom of the basin is situated around 4028 m according to Google Earth. The vegetation is made up mostly by separate patches of Paja Brava (Festuca orthophylla), which often grow in this characteristic circle arc format.
Must have been vicuñas (wild relatives of the llamas), I saw a few running in the distance in the eastern part of the basin. Planning to reach Alota before dark, I left the research area already before 4 PM. Isn’t really a must, but I’m a guest in the village and not sure about the quechua ethics regarding the dinner.
Llama herd on the outer slopes
The track I follow on the way to the village is flanked by quinoa fields. Beside the llama meat this plant is the other basic food of the local population, between the very few which can grow at these elevations. It seems that the spring work (sowing) has already started in some parts.
Trying to do a shortcut as the road turned too much to the left, around sunset I reached the wetland situated south of the village
Beside the flamingoes this is a very common bird species here. Sometimes they will fly round just a few meters above your head, while screaming. Not a welcome sign, I guess.
Altocumulus lenticularis is by far the most common cloud type here. Must be very windy at the highest elevations.
It seems that I will not make it to the village during daylight. The marshland’s topography forced me to turn to the left myself too, like I was corrected by an invisible quechua policeman because I did not follow the local rules. No bad feelings, I really like the ambiance here. More adventure, the better.
Am I right?
Okay, I reached the bridge
The cool evening wind is an early precursor of the cold night what will follow it. I reached Alota shortly before 8 PM after an almost 20 km hike, much more than the direct line which shows only 12 km.
Early morning in the remote village, the sky is clear, the wind has gone
Far from the previous day’s sunny afternoon
You can buy coca leaves here (legal in Bolivia), a mild to medium (if you chew as much as a cow) stimulant, frequently consumed by the locals. Be sure your mouth will feel numb as after a visit to the dentist.
The small green bag on the big one: As you can see I’m prepared for the long hike, three sunny days (read it as UV blast) and two cold nights are waiting for me
The weather warms up quickly and the first daylight hours are basically windless. This seems to be a general pattern here, which often extends to around noon, the wind starting to increase only in the early afternoon.
The work of the night
The wetland has a rich and variate fauna even in the dry season, beside the bird species there are many llamas, sheep and even bovines
As I heard they leave the area only in the winter months (June-august), so possibly returned here not long before
First I want to visit a canyon area, which is situated a few km’s to the east from my main target
The warming continues, without wind the temperature differences are very noticeable
Reaching higher elevations, I continue the hike on rougher terrain
Like it was cut by a giant guillotine
The top part is very fragmented, thus after meandering my way through the rock-labyrinth for some time I concluded it’s a bad idea to continue, trying to go round all these ravines and decided to return before heading to the endorheic basin. I have a heavy backpack with limited water for a big and more strenuous bypass. Let’s be reasonable.
NO, the decision is fixed
Noon approaches. One can almost sense the UV burn just looking to this picture.
Extensive quinoa fields on the other side, a reminder that this barren place is not entirely forgotten. Jubina mountain is in the right side of the background, that’s my direction.
The water in the stream is surprisingly balmy. I suppose it’s a hot spring area, I don’t think the daily warming itself could do this. However, careful with the drinking, many llamas are present in the surroundings. I mean DON’T.
Crossing the terrain transversely is not that straightforward even is there are no topographical obstacles of major scale
Or are?
I see now, that’s actually the main canyon, the more visited one. I was in a secondary one, though likely the same spectacular. Maybe I miss the GPS a little.
Crossing the shallow river. If not before, now I am using the “legionary hat” as my face started to feel the abrasion caused by the intense radiation. And not only the face. The exposed parts of the skin (which are pretty large as I am wearing shorts and T-shirt) are continuously attacked from various directions. Doing a lot of outdoor activities in all seasons from many years, I think that never felt burning sensation on my arms and calves before since childhood. But you can’t really prepare to this level of UV intensity (13-14 now), it’s clearly above the European scale.
Another small scale ravine on the other side. Look, a viscacha! Oh, it’s gone, had no time to record it. Very quick, likeable creatures, with their appearance somewhere between a rabbit and a squirrel.
The campesinos (local farmers) working on the quinoa fields. Well, even if they live here from centuries, are fully clothed and are using hats…
A little later I reached the dirt road where the 4wd cars circulate towards Laguna Colorada and the Siloli desert. Jesus’s heart was present and I received a full bottle of water (did not asked for) from a kind female tourist after stopping to curiously ask what the heck am I doing here alone with a heavy backpack. Now I’m sure I will stay both nights outside.
Reaching the col of the basin. The slightly undulating terrain was misleading as there were more topographical discontinuities than one could conclude simply looking from the distance. A little tired until now, the elevation taxes you and it’s different with a bigger luggage.
On the cracked bottom of Laguna Seca, which locals told me is the name of the place studied by me. Proper name.
WHAAAT !? This was one of the biggest and most pleasant surprises of all my cold-hunter career until now. NINE degrees below Alota, which itself is already on the bottom of a flat basin? This is the definition of a Jackpot. And the following two nights could even beat that! How about the 33.3 degree amplitude?
Yeah, some vivid colors there. Maybe I too should have used Mr. Barani’s helical radiation shield?
After scanning the surroundings I decided to spend the night a little higher on the southern slopes of Jubina mountain. Spotted there a rudimentary building, which later identified as related to a nearby small-scale mining activity. Shortly after I changed my mind seeing a lot of rodent feces in one corner inside the rectangular walls. I like animals but don’t want to wake up with jerry on my face…
More exposed to the elements, but another level of freedom. Good night! Wait, it’s only around 5 PM or so.
Park ranger feeling. Not the best payment, but nice view.
Now seriously: Good Night!
Was the night good? To be honest, far from my favorite one. Despite the optimistic forecast regarding a completely clear sky, from the late afternoon well into the second part of the night there were constant altocumulus invasions like the place was seriously cursed. And the previous one – which I decided not to spend here – was spotless, despite the forecast showed partial cover. The westerly clouds are just coming and going, but never disappearing completely. I fell asleep late, but when woke up around 4:30 AM the sky was clear and there was barely any air movement. Great! My thermometer showed -3 degrees, must be a strong inversion down there. Soon I was ready to an early morning visit to the weather installation.
Indeed, in the lowest part of the basin it suddenly felt colder. The air was completely still. I guessed well, the minimum is well below -10, but less cold than the previous morning. Not bad after the altocumulus marathon.
No T-shirt time anymore, the lack of rest also weathered me a little
Sunrise above Cerro Tomasamil (5890 m), the highest peak you can see from my research spot (around 50 km as the bird flies)
That likely was a vicuña, but what killed it? A cougar (puma) could be part of the equation, no doubt
Around 8 AM already reaching the positive range, that’s a serious leap!
Lord of space and time
This is what I talked about a little earlier: there are a few crevices in the rock nearby, which evidently are anthropic. Then I remembered the conversation with the quechua woman in Alota regarding Jubina mountain: “it’s very rich, silver, gold and many other”. Maybe they think I am a gold-digger in disguise?
Until the early afternoon he weather warmed even above yesterday’s maximum. You can’t really comprehend it’s the same day on the same spot.
Maybe only the pretzel shaped tufts of paja brava know what this remote basin’s climate is capable of
The second night was completely clear, though somewhat windier in the evening. As at dawn the mobile thermometer showed -5 degrees at my camp, I knew it will be even colder on the bottom this time. And it was: -16.5 degrees, the lowest temperature until now.
The golden mantle lowering into the depression
I left the research spot in the morning and hiked back the roughly 20 km’s to Alota. This must be the dwelling-place of a llama herder, but nobody at home now.
Gotcha! Culpeo fox
The vicuñas are the ancestors of the alpacas, also related to the llamas. Very common on the Altiplano, you can spot them often near the road while passing by car.
Hitchhiking around noon in UV-strucked Alota. A few years ago the road was paved, so now it’s pretty easy to reach Uyuni with basically any means of transport. I was lucky that the Calama bus (from Chile) passed there less than 30 minutes after my arrival and of course the fare was very cheap.
Train graveyard in Uyuni: Until the late 19. century the silver mining in Potosí declined thus the carriages transporting the mineral to the Pacific coast through the Atacama were left pray to the time and elements.

In the evening of the return I observed signs of a respiratory infection which intensified the next day (likely flu), so I decided to take some rest. Regarding the original plan this meant a single important change: there will be no climbing. Hard to accept it, but that was the proper rational decision. I have to return to collect the equipment in less than a week, so I will not play the Russian roulette. That’s it, next time. I still went out to visit the train wreck at the periphery of the town. Interesting, but…
too bad for the garbage field you have to cross from and to the settlement if you come by foot
My condition didn’t improved – to say the least – so stayed mostly inside the following day, but afterwards I felt somewhat better and went out to a walk again. This time the purpose was to identify the weather station, which I concluded it must be somewhere in the area of the airport (some 5 km from the center). I want to visit it and, if possible, obtain some data to compare it with my measurements. As I couldn’t see it from the road and did not know the local rules regarding the airport security (saw soldiers patrolling inside the fence), decided to return and ask the hotel staff regarding this.
My hotel room
Feeling stronger it was time for a longer trip. I visited the Salar de Uyuni, one (more correctly THE) of the country’s main attractions. At 3660 m elevation, the extensive saltpan is the worlds largest measuring over 10.000 square km and almost 150 km across. You heard it right.
As in case of many other scenic places, tourists arrive here through organized group tours (one or more days) by jeep. However, for eccentrics like me is more palatable to do this “freestyle”, so I reached Colchani village by bus (less than US $1) and continued by foot. From the asphalt it’s 4-5 km to the edge of the salar. Under the spell of the infiniteness I could not resist and just walked and walked forward. After a while I saw something in the distance, of which first wasn’t sure if are cars (there is also some exploitation near the shore) or some flatter buildings, but later turned out to be the latter. It was a complex built in and from salt. For tourists of course.
Does it look a little like Antarctica maybe? Be sure, it’s only the look as the UV radiation is at a different level here.
The place is named “Dakar Monument” and concluding from the walking time must be around 8-9 km inside the salar
On the way back. Convective clouds are evolving above the eastern ranges (towards Potosí). The hike was technically easy (very flat) but pretty long (26-28 km) for a “warm-up” after the flu. However, the distance per se should have not be an issue. The problem was the notorious radiation, more specifically the reflected one. I read that a sunglass is a must here, but as I didn’t felt anything suspicious regarding the vision while hiking, just continued without protection. Bad decision. The inflammation started only in the evening and wasn’t over the next day. How can I describe the sensation? Well, imagine that your eyelashes became your worst enemy. You can’t close them because they will feel like wires scratching the surface of your eyes. So, good night…
On the third day following the UV incident my vision improved sufficiently to can safely return to collect the equipment. It was also the planned date to do this. After some less potent days, the forecast shows a new cooling in progress, so I was optimistic regarding this last night which I will spend in the wilderness. Taking the Calama bus at dawn, started the hike from Alota in the morning. It was pretty chilly, definitely below -5 degrees. This time I continued to stay on the main road more, turning left towards Jubina only after about 12 km’s. Reaching the periphery of the closed basin I observed two people so entered in conversation and found out they are herders searching for some missing llamas. Told them I only saw vicuñas inside the basin.
Reaching the bottom I tried to identify the tripod as soon as possible, but as I approached it became clearer and clearer that something is wrong. The suspense was over after finding the structure in its place, though overturned. So: wind, animal or human? Turned out to be the first as both the falling direction (towards east) and the time of the incident, which I concluded later from the interrupted graph (between 3-4 PM) supported this theory. As the weight-reinforced installation felt pretty stable and easily bearing the first days wind, those gusts must have been wild.
Inspector gadget is back
Restoring the measuring equipment
Around noon the radiation was over the scale again, hard to found a shelter in this period as the sun is very high on the sky
Feeling well, decided to do a hike to the top of Jubina
Queñoa (don’t mistake it for quinoa), the highest living tree in the world has an easily exfoliating surface
The other endemic plant of the highest elevations is the Yareta (the moss looking one), which often lives in a symbiotic relationship with the former. But don’t be fooled of the aspect, it’s hard as a rock.
Wind and UV: On top of Jubina (around 4400 m). I wouldn’t consider it a “true climb” – in the bigger context it’s more like a hill here – but it was the highest point I reached during the journey. RIP Garmin watch, I lost you here...
Maybe my favorite plant? Definitely special.
Close-up of a yareta
Almost like another planet
The thick foliage of the queñoa evolved to can endure the drought and the strong wind of the barren plateau
Panorama of Laguna Seca
Alota in the opposite direction
Uturuncu (6008 m) the highest mountain in southern Bolivia and the salt flats of Laguna Yapi (4000 m). The whitish top of the mountain is not snow, but volcanic debris
Zooming the bottom of Laguna Seca. Yes, I can spot the weather installation.
Descending the rocky slopes. The return to the camp was straightforward and also much faster then the wandering on the bumps of the plateau
Colors and waves of the Altiplano
Are you looking for me? Not today.
IR and UV are gone
Last morning temperature check: The evening and night was completely clear and also the calmest of all, thus the temperature plummeted extremely low, reaching -19 degrees just before sunrise. What a finish!
Some martian vibes
The endorheic basin exceeded my expectation
The research is over, the results are excellent
Darwin’s rhea (Suri) tracks in the sand near the basin’s col
The hike back to Alota was the same long (if not longer) as this time continuously followed the trails between the quinoa fields, without trying to do shortcuts
Arriving to Alota space center 🙂
Guardians of Uyuni. After hitchhiking for a while, a truck coming from Chile took me back to the town, same cheap as the bus.
Some soviet influence?
Everything is revolving around tourism in Uyuni, the small town is full of agencies, accommodations, souvenir shops and small restaurants. But of course, I was more interested to get in touch with the weather station. The problem was resolved with the helpfulness of the hotel staff who arranged a meeting with the weather personnel of the airport. The data I obtained there is valuable (see the third chapter)
A lost sherpa? The descendants of the incas might be of smaller stature but they’re far from weak
Nothing more bolivian than this colorful load-pack
It was time to start the return. Following the same way by bus, first I reached Potosí
The well decorated “church of indians”, unfortunately not open for visitors
The top of San Francisco church overlapping with the pyramidal peak of Cerro Rico (author’s fault)
Now the “Casa National de la Moneda” was open and I take the opportunity to visit it in the last hours of my stay. It’s Sunday and pretty crowded because of the short program, but worth the patience.
“Triangular virgin”, a mix between the new Christian religion and the older native mountain veneration
Some old coins from the early minting style (16-17th century)
Inside the chamber with the huge gears which operated the mint
In the mineralogy sector
There is even a church inside
Pieces of art made from the abounding local silver
The next day I continued the bus trip to Sucre
Despite the poor statistics in comparison to other South-American countries, Bolivia’s “second capital” radiates a general feeling of prosperity and proudness
Uncheangedly white
From Sucre I descended to the savanna climate of Santa Cruz with the 45 minute local flight. The same journey would take 11 hours by bus and the cheap prices support the good decision. Again hot and windy. And dusty.
At the local zoo
Only South-American fauna
Not the car…
…but the same strong and fast
He just stood up and elegantly walked like this for a while, before changing into tree-acrobatics mode
Nandu. A smaller relative lives also in the Altiplano (remember the tracks in the sand?)
The geometrically designed armadillo
Well, I think we’re not completely done here. Hasta luego, amigos!

to be continued…

Laguna Seca: where summer meets winter (3/3)

Interpretation of the logger’s graph (using LogTag Analyzer 3 software)

The temperature curve of the 10 days/ 10 nights research period. The device was registering a value every 2 minutes.

First day and night (17-18th September)

I installed the measuring equipment on the bottom of the endorheic basin in the early afternoon during moderately windy conditions and almost clear sky. The logger set for 2 minute intervals was started at 2:56 PM and the first reading showed 14.4 degrees Celsius. Concluding from both the time of the day and the temperature curve it was around the hottest part of the day, reaching the slightly higher maximum of 14.7 degrees at 3:25 PM. I left the equipment before 4 PM and hiked back to Alota under generally clear sky with some altocumulus lenticularis clouds over the higher mountains. The moderate wind persisted also in the evening.

The temperature curve of the first afternoon and the following night

After a smoother afternoon start the temperature drop is slightly disturbed in the evening and night but generally is pretty straightforward. Descending below 0 for first time at 10:35 PM, the continuous negative values started right around midnight. The minimum of -16.2 C was reached at 5:11 AM and was approached again with -16.1 C at 6:25 AM before sunrise. I spent that night in Alota and measured -7 degrees outside in the early morning during clear and calm conditions.

Second day and night (18-19th September)

After sunrise the temperature rise is fast and clean, already passing over 0 degrees around 8 AM. Later the curve becomes less and less abrupt but has a general constancy until around 3 PM, reaching the peak of 17.1 C at 3:49 PM. Together with the -16.2 C morning minimum this means a 33.3 degree temperature excursion in the same day. The obvious drop starts around 4:30 PM becoming more pronounced after 5:20 PM. Like in the previous night’s case, the afternoon drop is the cleanest while the evening and first part of the night somewhat disturbed, still without significant changes on the higher scale. The 0 degree mark was passed for the first time at 11:21 PM, while the continuous negative values started from 0:45 AM. The minimum of -15.2 C was reached at 6:17 AM.

The temperature curve of the second day and the following night

I spent the night in the basin at my camp situated a little higher, outside the inversion layer on the southern slope of Jubina mountain. Despite the optimistic clear forecast, from the late afternoon well into the night there were constant altocumulus (also cirrostratus) invasions, passing from west to east and partially covering the sky between 1/8 and 5/8 ratio. The wind was generally weak, reaching the lowest speed at dawn when the sky finally became completely clear. I was present at the research spot during the coldest period before sunrise and observed calm conditions on the bottom.

Third day and night (19-20th September)

I continued to stay in the basin observing an all day long clear sky. The very rapid temperature rise passed again above 0 degrees around 8 AM, the curve becoming less abrupt before 9 AM. This time the maximum of 17.8 C was reached a little sooner at 2:15 PM, which together with the -15.2 C morning minimum represents a 33.0 degree daily amplitude. The warmest early afternoon period is characterized by pretty big 1.5-2 degrees small scale oscillations in short periods of time. The general drop started after 4 PM and again the cleanest part was the late afternoon. The evening and especially the night was less stable, where a 5 degree warming happened around 2 AM and only after that started to drop rapidly again. It reached below 0 for the first time at 11:17 PM, while the continuous negative temperatures started from 0:35 AM. The minimum of -16.5 degrees Celsius was reached at 6:03 AM, thus slightly exceeding the first nights low.

The temperature curve of the third day and the following night

I was present in the area, spending the night at my camp and checking the logger in the coldest early morning period. During the dark hours I observed no clouds at all and only weak, sometimes moderate wind on the slope. Regarding the earlier mentioned abrupt night warming, as I can’t recall any clouds on this night, the disturbance was likely caused by wind alone. On the bottom was calm again at dawn and morning.

Fourth day and night (20-21th September)

I left the research area after sunrise and hiked back to Alota from where traveled to Uyuni by bus. In Alota was still completely clear and close to calm around midday. The diagram shows the characteristic undisturbed morning warming, passing the 0 degree mark again around 8 AM and continuing the rapid increase above 6 degrees Celsius at 8:50 AM. With a more moderate but still generally constant ascending slope, the peak of 18.4 degrees was reached at 3:09 PM, which together with the morning’s -16.5 C represents an impressive 34.9 degree daily amplitude, the biggest until now.

The temperature curve of the fourth day and the following night

The obvious drop started after 5:30 PM, again cleaner in the late afternoon and more fragmented in the evening and night, but keeping the big lines. This pattern seems to be a generality here. The continuous negative values appeared early on at 9:57 PM. This time the lowpoint of -14.6 degrees was reached earlier, around 4:30 AM as after that was a significant increase to -6.8 C at 5:30 AM, dropping afterwards back to -14 around 6 AM. Wasn’t present, but probably wind disturbance again.

Fifth day and night (21-22th September)

I was in Uyuni on this day where observed a partially cirrus covered sky, spotting a few undeveloped cumulus clouds over the mountains. From the diagram the conditions in the Alota area are still stable, this time the fast morning warming raised the temperature above 0 already around 7:45 AM.

The temperature curve of the fifth day and the following night

The curve follows a very similar pattern as in the previous days, reaching a little higher peak (19.5 degrees) shortly before 4 PM. Then comes the cleaner afternoon drop and the more disturbed evening and night. Reaching 0 degrees at 10:13 PM, the continuous negative values started from 11:11 PM. With a low of -11.7 C around 6 AM is still a cold morning, though less frigid than the past ones. Huge 34.1 degree daily amplitude, second biggest until now.

Sixth day and night (22-23th September)

I don’t remember the sky’s state on this day as was resting inside my hotel room most of the time (flu). The day part of the temperature curve is similar to the previous one, exceeding 0 degrees after 7:30 AM and reaching the peak of 19.9 at 2:45 PM.

The temperature curve of the sixth day and the following night

The night cooling is somewhat similar (more disturbed after the evening) but weaker, reaching only -6.8 degrees at 5:35 AM, preceded by some 3-5 degree ups and downs in shorter periods of time. First negative value appeared at 0:29 AM and became continuous from 1:37 AM. The 31.6 degree daily fluctuation is still solid.

Seventh day and night (23-24th September)

Except some more developed convective clouds above the mountains in the east the sky was still clear in Uyuni. It’s the warmest day of the research, the 0 degree mark was exceeded already around 7:15 AM, while the maximum climbed to 20.3 C at 1:17 PM.

The temperature curve of the seventh day and the following night

No significant changes in the curve’s general pattern, but the drop is even less potent this time, becoming continuously negative only from 4:49 AM and reaching a mild -5.4 C low at 6:15 AM. The 27.1 degree amplitude is less pronounced than in the previous days when it was constantly well above 30 degree.

Eighth day and night (24-25th September)

On this day I made a longer hike to Salar de Uyuni where the sky was clear, observing developed convective clouds only above the eastern mountains. However, now the air was a little dusty with less visibility than in the previous days.

The temperature curve of the eighth day and the following night

Again, no mentionable changes in the curve’s rising part, shortly after 7 AM reached 0 degrees and raised to 19.4 C at 1:09 PM following the general “convex pattern”. This was followed by the weakest night, the temperature becoming negative only from 5:35 AM and recording the warmest low of -4.1 degrees at 6:33 AM. This was preceded by more than 6 degree short term ups and downs, warming up to positive 9.4 degrees not long before midnight. Compared to the first days, the 24.8 degree amplitude is also modest.

Ninth day and night (25-26th September)

Another less memorable day regarding the ambience as was again mostly inside because of UV damage to my eyes (reflected rays on the saltpan), but I remember it was pretty bright in Uyuni, as it seriously disturbed my vision around midday.

The temperature curve of the ninth day (interrupted)

The graph shows the same clean and strong morning rise with the temperature passing over the 0 degree mark not long after 7 AM and reaching 19.0 degrees at 1:55 PM. But at 3:13 PM the diagram is suddenly interrupted. I concluded that the tripod was overturned in this afternoon by the violent westerly wind and the sensor’s cable was disconnected due to the fall.

Tenth day and night (26-27th September)

At dawn I went back to Alota by bus, where the morning was quite chilly, likely below -5 degrees. After the 20 km hike I reached the research spot before 11 AM. Fortunately the trouble caused by the wind was only temporary and the logger could continue recording the temperature after reconnecting the sensor. The day was completely clear (only some convective clouds in the far horizon above the southern mountains) but windy again in the early afternoon when I made an ascent to the peak of Jubina mountain.

The temperature curve of the tenth day (first part missing) and the following night

The day’s maximum was 19.1 degrees Celsius and was reached at 2:39 PM. I’m pretty sure that today the amplitude exceeded the 30 degree mark again, but having no concrete data from the night this is only an opinion. Nonetheless, I have data from the following one which was the coldest in the entire research period. The first freezing appeared around midnight, while the continuous negative values started from 0:37 AM. Despite being again less stable in the late evening and in the first part of the night when we can observe 3-4 degree short term ups and downs on the graph, the completely clear conditions favorized to descend very deep in the second part of the dark hours, reaching an impressive -19.0 degrees at 6:23 AM shortly before sunrise. This together with the previous day’s 19.1 degree maximum gives a staggering 38.1 degree amplitude in under 24 hours. The logger was stopped at 7:01 AM when the screen showed -11.6 degrees.

The average temperature of the 10 days research is 5.7 degrees Celsius. The mean minimum is -12.2 degrees, while the mean maximum 18.5 degrees, which give a mean daily amplitude of 30.7 degrees. We can observe that the mean temperature is clearly higher than we could expect solely from the minimums and maximums, which is caused by the fact that the positive part of the curve has a rounded peak, while the negative one is much sharper, technically V shaped.

General conclusions

  • The sky is predominantly clear both day and night, altocumulus lenticularis being the most common cloud type.
  • The wind follows an obvious pattern: in the night and morning is weak or calm, while the afternoon is much more windier, when the westerlies are dominating.
  • The daily temperature fluctuation is huge, usually exceeding 30 degrees, possibly producing one of the biggest average amplitudes on Earth.
  • The warming after sunrise is much faster than the cooling after sunset, regularly reaching or exceeding 10 degrees in one hour.
  • Regarding the finer details, interestingly the short period disturbances in the temperature’s course are always bigger in the evening and even in the night than in the late afternoon when the drop is much smoother, but it seems that this doesn’t correlates with the wind speed.
  • More than 1 degree fluctuations can appear often in very short periods of time even in the coldest, virtually windless mornings.
  • There is a clear difference between the positive (related to the maximums) and negative waves (related to the minimums) of the temperature curve, the former having a rounded, while the latter a more angled shape. That means the cooling is pretty constant until the morning without approaching an equilibrium state (very low humidity), thus, before sunrise is often 15, but sometimes even 20 degrees colder than around midnight.
  • Due to the elevation and the tropical setting the UV radiation is extremely high.
  • There is striking difference between sun and shade, without wind the same temperature feels much warmer than at sea level.

Comparing my logger’s results with the official data of the local weather stations

After finishing the research I managed to obtain valuable information at Uyuni airport meteorological station, thanks to the helping nature of the hotel staff. Below is a chart with the minimums, maximums and amplitudes registered in the same time period:

Comparison between the researched endorheic basin and Uyuni weather station (degrees in Celsius)

The most obvious thing is the huge discrepancy between the minimum temperatures, Laguna Seca being colder with 6 degrees on average and 8-10 degrees during the frostier days, while in the milder (less stable) ones they are pretty close to each other. There is no doubt that this is caused by the much stronger temperature inversion in the closed basin, which manifests itself during the calmer periods. Even if Uyuni too is situated on the floor of a basin, the more extensive flat terrain doesn’t permit the same level of cold air pool formation.

On the other hand, the highest temperatures are very similar on average, the closed basin being even slightly warmer despite the higher elevation, which under the same circumstances should gave him a disadvantage of around 2-2.5 degrees. This is probably caused by the stronger föhn effect in the Alota region, where the western mountain ranges are much closer and the dominant wind is blowing exactly from their direction.

Weather data of Bolivia’s official stations (Ogimet)
*Uyuni does not appear in this chart

The partially missing Ogimet data shows that Potosí weather station which is situated on the eastern part of the Altiplano and higher than Uyuni (above 3900 m) had 19-22 degree maximums in this period (likely föhn effect too), but also much weaker minimums (-3, 2 degrees) certainly due to the more exposed topography.

Regarding the amplitudes, thanks to the big advantage on the low temperature front, Laguna Seca exceeds Uyuni with a good 6 degrees, but sometimes the discrepancy can be more than 10 degrees. While Uyuni’s biggest amplitude in under 24 hours was 28.6 degrees (from 19.4 to -9.2 degrees) in the period of my research, the closed basin reached 38.1 degrees (from 19.1 to -19 degrees). No doubt that this place can surpass 40 degrees in the best circumstances. Taking into account that Uyuni has one of the biggest average daily fluctuations of all the official weather stations I’ve encountered until now on the net, a place which is regularly 5-10 degrees ahead of this definitely can be considered worth of studying in the long term. The future is open as always, we’ll see.