Leaving around 4 am, we encountered no traffic until shortly before reaching our destination, the Bigelow Preserve, where we were stuck in stop-and-go traffic for 15–20 minutes; the traffic was trying to turn into the access road for the Sugarloaf ski resort, which was backed up. Due to a lack of winter road maintenance on Stratton Brook Pond Road, we parked on ME-27, where the Appalachian Trail crosses it; as it was a busy day on the trail, the parking lot was full, and we parked on the side of the road. We started hiking shortly after 9 am carrying our snowshoes but quickly decided to put them on. There appeared to be at least a foot of snow on the ground, and the trail was a bit icy at this point, with a satisfying crunching noise while walking, although the snow became much softer as the day went on and temperatures rose well above freezing. When the Appalachian Trail started to climb the mountain, which was quite steep at times, the several layers we were wearing became much too warm, and we both stripped down to just a t-shirt for the remainder of the climb.

As we gained elevation, the snowpack increased, to the point it was burying—or almost burying—the trail blazes at times. While the path others had taken before us was easy to follow, it wasn’t always actually on the trail, due to the difficult-to-find blazes, so we broke new trail in the snow in a few spots to return to the actual trail. Even when we were on the trail, it often involved pushing through fir branches—dripping with melting snow—since the snow was so deep such that we were above the region clear of branches. Once we reached the small, unnamed peak just east of The Horns Pond, we were rewarded with our first scenic viewpoint.

From here, it was downhill to the pond, before more uphill to South Peak, one half of The Horns. Next, there was significant downhill before the final climb to West Peak, where we broke out above the tree line and reached the summit around an hour before totality and around five and half hours after starting the hike.

At the summit, there was a brisk wind, so we quickly put on several layers, including winter coats, before eating lunch. There were also two to three dozen people at West Peak for the eclipse, and we could see more to the east on Avery Peak; some of these folks seemed rather ill equipped for the conditions, without snowshoes or even crampons (and there was one guy wearing sneakers). We decided to backtrack downhill slightly east and head south of the ridgeline to avoid the crowds and get in the lee of the ridgeline. Here, we began to set up our gear, which involved cutting out and compacting a ledge in the steep, snow-covered slope. As with the last eclipse, I used a 70-300mm telephoto lens at 300mm with a 2x teleconverter (and a 3D-printed solar filter holder) on a 1.6x-crop-factor camera (although a newer camera than last time) and also used my Ricoh Theta Z1 panoramic camera (instead of my Theta S like last time). Instead of bringing a full tripod, I brought just the head from my tripod and a small makeshift tripod I made the day before out of three 18″-long, 1″-square, birch dowels and a 3D-printed plastic junction. This was much lighter and fit inside my day pack, along with a monopod for the panoramic camera, which I jammed into the snow, but it was still a very-heavy day pack between all of the camera equipment, water, extra layers, etc. The setup process was a bit rushed, and I only finished a few minutes before totality began. Thus, I didn’t have time to carefully focus my lens on sunspots and had to rely on autofocus, which ended up being slightly off (and my brother was also slightly off on the focus of the telescope he brought).

The trip and climb were well worth it. Not only were there perfect skies and amazing scenery, but you could see the moon’s shadow approach and then leave over the landscape, and there was a great view of the horizon and the sunset-like sky above it.

Afterward, we sat around and watched the sun for a bit before packing everything up and starting to head down, around an hour after totality. We were the last to leave, besides a couple and their dog. Instead of going down the way we came, we took the steeper and more direct—and thus shorter—blue-blazed Fire Warden’s Trail. In particular, this trail did not go over any other peaks, so it was all downhill until the base of the mountain, after which there were some rolling hills and an uphill to reach the road and the parked car; this was important, as I was rather sore at this point, particularly with the heavy day pack and the unusual gait required with the snowshoes. After passing four or five people on the trail, we became stuck behind a dozen or so (what I assume were) undergrads in some sort of organized group—some of whom were rather timid about the steep downhill on soft snow and thus pretty much stopped; after they let us pass, we were able to make reasonably-fast progress the rest of the way down the mountain, although I was sore and thus slow on the uphill sections after that (and was definitely slowing my brother down). We made it back to the car at dusk, around 8 pm, roughly three and a half hours after leaving the summit and eleven hours after beginning the hike.² In total, the hike was 14–15 miles long, with several thousand feet of elevation gain.

After the hike, we stopped at Sugarloaf for my brother to go for his daily run, where there was bumper-to-bumper traffic leaving; clearly, Sugarloaf held some sort of event after the eclipse, since it was dark, and they don’t have night skiing. When we left Sugarloaf, the traffic was gone, although we eventually caught up to it. Once we stopped for dinner, that traffic was also gone, and we encountered no other traffic on the return trip, for what ended up being a very long day trip.

1. I was carefully checking both the ECMWF cloud forecast online and loading the NWS National Blend of Models into QGIS, with roads, borders, and the region of totality overlaid. ↩

2. The folks we passed on the way down clearly did not make it back before dark (although the undergrad group looked like they might have been planning on camping), and there were still several cars parked along the road when we left. ↩

As one might imagine, getting to Antarctica is difficult, both due to the remoteness and the harsh environment. To start, I flew commercial from Boston to Christchurch, New Zealand, via San Francisco and Auckland, which requires 19–20 hours of flights, plus layovers.² The next day, I arrived at USAP’s clothing distribution center (CDC), just outside the Christchurch airport, for COVID testing, a brief introductory presentation, and to try on the program-issued extreme cold weather (ECW) gear. At this point, we learned that our “ice flight,” our flight from Christchurch to McMurdo Station, was scheduled for three days later. McMurdo Station is the largest research station in Antarctica, and it serves as USAP’s primary base on the continent; all personnel and cargo headed to the South Pole pass through McMurdo. All personnel head to McMurdo, as well as New Zealand’s adjacent Scott Base, pass through Christchurch. While we had a couple days in Christchurch, we were under strict isolation instructions due to COVID, although I did get to walk downtown and see the lovely Christchurch Botanical Garden.

After some additional training held online and another COVID test the day before our flight, we were ready to depart. The day started with waking up well before dawn and calling the flight status hotline to ensure the flight was not delayed. Due to the harsh and unpredictable environment, flights are frequently delayed due to weather or mechanical issues. Upon arrival at the CDC, we donned our full ECW—in case of a flight emergency—and proceeded to check in. We were weighed along with our luggage, such that extra cargo could be added right up to the weight limit. Most of our cargo was packed onto pallets, with the exception of a small carry-on bag. One checked bag was designated a “boomerang bag,” which we would get back in case the weather deteriorated at McMurdo and the flight had to “boomerang” and return to Christchurch, becoming a very long flight to nowhere. There was then enough waiting time to grab something for breakfast at the nearby supermarket, after which we were bussed onto the tarmac to board our flight. As I was flying in early-to-mid December, this was on an NZDF C-130 aircraft; early in the season, flights are primarily on USAF C-17 aircraft, but as temperatures rise and the runway softens, this switches to lighter NZDF C-130 aircraft and finally to ski-equipped NY ANG LC-130 aircraft. Next came the >7 hour flight to McMurdo, which, while uneventful, was loud, uncomfortable, and packed full with both personnel and cargo pallets. As we proceeded south, sea ice began to appear, and then we finally saw the outer reaches of the Antarctic continent (the C-130 only has a few small windows, so folks had to take turns looking out).

Finally, we landed at Phoenix Airfield on the McMurdo Ice Shelf and were then driven to McMurdo Station in the Kress Transporter for our arrival briefing. In the summer, the air temperature at McMurdo hovers around freezing, so a flannel shirt, fleece jacket, and windbreaker—along with a wool hat and gloves—were enough to stay comfortable outside (at least if one wasn’t just standing around). After an initial “night” in Building 140,³ we were tested for COVID again, and I then settled into my home for the next two weeks, a room in the Hotel California (HoCal) dorm, with a lovely view of McMurdo Sound, Mount Discovery, and the Royal Society Range.

We were scheduled for five days of quarantine, but once that was up, the weather finally improved at the West Antarctic Ice Sheet (WAIS) Divide field camp, after the better part of a month, so the LC-130 aircraft were prioritized for trips there. The South Pole was a backup destination the entire week, which meant in addition to not flying, we also had to live out of our single carry-on bag, since the rest of our luggage was on pallets ready to be loaded should the weather at WAIS deteriorate. Although unplanned and uncertain, the extended stay in McMurdo was not all bad, as I got to go hiking in the vicinity of McMurdo; see Discovery Hut, built for Scott’s Discovery expedition and also used for his ill-fated Terra Nova expedition; and see the launch of the SPIDER balloon-borne telescope. For the latter, we were not allowed to take the shuttle vans out to the Long Duration Ballooning (LDB) facility for the launch as we were quarantining, so I borrowed a fat-tire bike and biked the 13–14 miles round trip to near the LDB facility and Williams Field, a.k.a. Willy Field, to get a closer view of the launch. I also got to see plenty of seals and skuas,⁴ as well as a single Adélie penguin off Hut Point, probably the first Spheniscidae visitor of the season.

As we had still not flown by December 23, we were stuck for the weekend. Normally, Saturday is a work day in Antarctica, but Christmas was observed on the 24th, so in addition to there being no flights, we also couldn’t take part in the festivities as we were in isolation. On Monday, we were finally the primary flight and were driven to Willy Field for our flight to the Pole.⁵ After a few hours waiting around the airfield for mechanical issues with the LC-130 aircraft to be addressed,⁶ we boarded the aircraft and began to taxi. Unfortunately, the aircraft was still having issues with its hydraulics, so we deplaned and returned to McMurdo for another night. On Tuesday, December 27, we returned to Willy Field. During the ride to the airfield, it was unclear if the weather would hold, but it ended up cooperating and we quickly boarded the LC-130 soon after we arrived and departed for the South Pole.

After a three-hour flight, we landed at Amundsen–Scott South Pole Station’s Jack F. Paulus Skiway and taxied to the ramp adjacent to the station, where we deplaned with the props still spinning as the cold makes it difficult to start the engines. Here, the weather was much colder, so the ECW gear was very much necessary; it is also very, very, very dry. After an arrival briefing and lunch, I went straight to work, helping with the installation of a detector module that a colleague on my flight had carried. Other than the day I left in February, I went out to the “Dark Sector,” which has restrictions on radio transmitters, to work on the telescopes every day, specifically in the Dark Sector Laboratory (DSL) and Martin A. Pomerantz Observatory (MAPO) buildings. In addition to assembly, installation, and calibration work on BICEP receivers, I also overhauled the computers running the BICEP3 telescope, which was the primary reason for me to deploy.

The South Pole Station is located at ~2800 m (~9300′) elevation, on the desolate Polar Plateau, with nothing besides the Station for hundreds of miles. Despite the extreme conditions outside, life in the current elevated station is pretty normal, once you get used to the fact that the sun never sets during the summer. Meals are served in the galley, although without any fresh fruit or vegetables most of the time, and the berthing wings consist of single-occupancy dorm rooms, albeit very small ones. There’s a science lab, gym, post office, store, medical clinic, laundry room, music room, arts & crafts room, sauna, greenhouse, and a couple lounges. However, there’s severe water rationing, with a limit of four minutes of shower water a week, typically a pair of two-minute showers, and one load of laundry. Internet access is also extremely limited; depending on which—if any—geostationary satellite is visible, it ranges from very slow and high latency to practically unusable to no access at all.⁷ Although I missed Christmas dinner being stuck in McMurdo, I did get to attend the New Year’s Eve party, held outside due to COVID, and the yearly Geographic Pole remarking ceremony on New Year’s Day.⁸ Thanks to the unique weather, sun dogs and related atmospheric optical phenomena are frequently visible.

As the end of the summer season neared in February, temperatures began to dip below −40°, with the wind chill pushing it significantly lower. I left the Pole on an LC-130 on February 15, the last flight out for the season, with around two dozen others; due to the extreme cold, there are no flights in or out until late October or early November, and the 40-ish people on the Station right now are isolated from the rest of the world. After arriving at Willy Field at McMurdo, we took “Ivan” the Terra Bus straight to Phoenix Airfield to wait for our flight to Christchurch. Our C-17 landed during the drive between the airfields, and after waiting a couple hours on the ice waiting for cargo to be unloaded and loaded, including a helicopter, we boarded the aircraft for a five-hour flight off the Ice.⁹

Upon arriving in Christchurch, it was dark and raining, a significant change from Antarctica. In addition to the sound of the rain, the humidity, the sounds of birds and insects, and the presence of smells¹⁰ are the drastic differences one notices upon leaving the Ice. After returning my ECW gear at the CDC and arriving at my hotel very late, I took a very long hot shower and went to bed. I had arranged for two extra days in Christchurch, so the next morning I booked a hotel room for the next two nights; the hotel room for the initial night was booked for me by USAP, and given the prevalence for flight delays to and from Antarctica, making arrangements in advance is risky. The first day, I visited the Christchurch Botanical Garden a second time, visited the Christchurch Art Gallery, and took a public bus out to go hiking in the Port Hills between Christchurch and Lyttelton. The next day, I took a bus to Lyttelton and a ferry across Lyttelton Harbour to Diamond Harbour and hiked to the summit of Mount Herbert, the tallest peak on the Banks Peninsula. The scenery was gorgeous, although it did rain a bit that morning. The next day was the long return trip to Boston.

I’ve uploaded more photos of both Antarctica and New Zealand to albums on Flickr.

1. And, yes, I got back almost six month ago and am just writing this blog post now. ↩

2. I had a very long layover in Auckland, although this did allow me to take public transit downtown and see parts of Auckland. ↩

3. The sun never set in my two months in Antarctica. ↩

4. Skuas are essentially large brown seagulls. ↩

5. Phoenix Airfield is a compacted-snow runway used for wheeled aircraft, while Willy Field is a skiway used for ski-equipped aircraft. ↩

6. We fortunately could spend time in the airfield galley and also got a tour of the control tower. ↩

7. Besides 24/7 email access on certain shared accounts, over Iridium. ↩

8. Due to movement of the ice sheet, the location of the Geographic South Pole moves relative to the Station. ↩

9. Unfortunately, this meant I did not get to see any more penguins. ↩

10. Not smelling much at the South Pole is probably a good thing, given the dearth of showers. ↩

A colleague of mine working on the CLASS project and I left our accommodations in San Pedro de Atacama shortly after 5 am² and met up with some associates from the ACT project, in a second four-wheel drive pickup truck, at the start of the Jama road (CH 27) at around 5:30 am. As with previous climbs of Lascar and Cerro Toco, we informed others of our plans and took a satellite phone and satellite-based locator beacon as precautions. We then proceeded to drive toward the Argentinean border, to kilometer 147.5,³ arriving just before 7 am. We then turned off the Jama road and began following a dirt track north after crossing the buried gas pipeline. As it was still dark, finding the turn-off was somewhat challenging, although once we found it, following the dirt track was not too difficult (but a bit bumpy). We stopped to watch part of the sunrise over Laguna Helada.

As we continued to drive north, we crossed two washes. The first had some water, but the second was dry; neither presented any challenge to cross. Shortly after 8 am, we reached Río Zapaleri, at a location just upriver from where the Quebrada de Chicaliri tributary joins. While tracing out the route to the mountain on the satellite imagery, I was concerned that we would not be able to ford the river here. No accounts of previous ascents involve taking this route. Most cross the river at the Argentinean border and climb via the gulch just over the border⁴ or ford the river on foot and climb by a similar route. The tracks visible in the satellite imagery showed that the standard route was considerably better traveled, crossing the border at “Paso Zapaleri.” However, this would result in a significantly longer climb, which I sought to avoid. Fortunately, we were able to ford the river at the Quebrada de Chicaliri confluence without difficulty, although our pickup truck’s high clearance proved essential in doing so. This year, February and March were drier than normal, and our March 16 climb was a week after the last time it had snowed on Zapaleri (per Planet Labs satellite imagery); if it had been wetter, we might not have been able to cross.

We then drove out of the ravine⁵ and continued north toward the Bolivian border. Around 2.5 km from the Bolivian border, we turned off the established track⁶ toward the northeast and began following the bottom of a ravine in the direction of the Zapaleri summit. We continued up this ravine until the combination of the steep slope and the high altitude meant that we did not have sufficient engine power to go farther, even in 4L, and then parked the trucks perpendicular to the slope shortly before 9 am. My prediction for the trailhead based on the satellite imagery and digital elevation models proved to be quite accurate; GPS coordinates put the location where we parked only ~20 m from the location that I had marked on the map before setting out.

As Zapaleri is rarely climbed, and even more rarely climbed via the route I planned out, there was no trail. We began our climb by heading east, to the top of one of the ridges that border the ravine we drove up.⁷ We then followed this ridge to the northeast until it met a larger ridge. We continued climbing to the northwest along the larger ridge to near the summit. In retrospect, the climb would have been easier if we had climbed parallel to the ridge but slightly downhill from it toward the northeast. This would have avoided climbing over some of the outcroppings that are along the ridge and kept us out of the wind. However, the climb along the ridge provided an outstanding view toward the southwest, which we would have missed if we had stayed out of the wind.

Next, we turned toward the northeast and headed for the summit. The final summit is quite impressive and abruptly sticks up from the rest of the mountain.⁸ The only non-technical route up it is from the west, and this involves a scramble up an extremely steep slope comprised of loose rock and scree. If we had known this in advance, my colleague and I would have brought climbing helmets, which I would recommend for safety. We climbed the slope while following the base of the cliff face, since this gave additional hand-holds. We climbed one at a time and stopped at regular intervals in areas of more secure footing to allow each other to catch up, since this reduced the risk of being hit by rocks that were knocked loose.

Finally, we reached the summit at ~1:15 pm. The summit contains a three-sided painted steel border monument and is surrounded by steep drop-offs. The view is incredible. Additionally, if one walks north of the border monument, the bright green crater lake is visible.⁹ Although the mountain is not climbed particularly often, we did find a note left by recent climbers in a small, empty liquor bottle; apparently, a group of Argentinian narcotrafficking police officers climbed on 24 December 2020.

Using the Shuttle Radar Topography Mission 1-arcsecond (~30 m) digital elevation model (DEM), I calculated an elevation profile for the climb. According to these data, the approximately 2.4 km climb had ~630 m of vertical gain, resulting in an average grade of ~26%; the maximum grade was ~48%. However, the DEM does not have the resolution necessary to resolve the summit features, and the final push to the summit was almost certainly even steeper. Additionally, the DEM seems to systematically underestimate the elevation, at least when compared to the GPS track I recorded (which put the summit elevation at ~5700 m).

After around an hour at the summit, we began to head back down. While my colleague from CLASS had made it to the summit with me, our associates, some of whom were not as well acclimatized, did not, although some came close. We climbed slower than we would have otherwise and waited at the summit for them to catch up, but with the wind and the cold, waiting around while not moving is not particularly pleasant, and we eventually gave up and departed. The way down from the summit proved to be the most difficult part of the climb. Due to the steep slope and loose rocks and scree, it involved mostly sliding down on one’s derriere and using one’s feet and hands to try to not slide too much and to not knock loose too many rocks. Once down from the summit, the rest of the climb down was not too bad, although the steep slope again made progress somewhat slow. We stayed downhill from the ridge we had climbed up on, to stay out of the wind. We made it back to the trucks at around 4 pm, seven hours after we had started climbing. I ended up going through around half of the ~3.5 L of water that I had carried. After a brief rest, we began driving back to San Pedro de Atacama. Driving both to and back from Zapaleri, we saw many, many herds of vicuñas,¹⁰ and on the way back, we also saw a half dozen puna tinamous. We made it back to the paved Jama road at ~5:30 pm and back to San Pedro de Atacama at ~7:15 pm, roughly 14 hours after we had left.

After returning to the United States, I did some research on the origin of the summit border monument to try to determine when it was installed. The best resource I could find on this was a 1953 report on marking the border between Argentina and Bolivia (which is also where the 5648 m elevation I used in the first sentence of this blog post came from).¹¹ In addition to a written description of the border and survey, the report contains detailed maps, photos, and drawings of the border monuments.

Although the border between Chile and Argentina was surveyed and marked around 1900, the summit of Cerro Zapaleri was neither surveyed nor marked at that time.¹² However, the Argentina–Bolivia survey, which started in 1939, did mark it on 30 November 1940.

If one compares the photo and drawing of this original border monument to the photos of the current one earlier in this blog post, it is readily apparent that the current one is much shorter than the original 3.5 m tall monument, approximately half the height. A closer inspection of the cross-bracing reveals that the monument was not just shortened but that it was completely replaced; the cross-bracing on the current monument is installed on the outside of the angle irons instead of on the inside,¹³ and the bracing on the current monument connects to the angle irons farther from the top of the monument than on the original. Unfortunately, I was unable to determine when or why the monument was replaced. However, graffiti on the current monument mentions years dating back to 1997, so the monument was clearly replaced sometime before then. In addition to the monument, I located three brass survey markers. The Bolivian Instituto Geográfico Militar installed a triangulation station marker and an associated reference marker in 1965, and the Chilean Instituto Geográfico Militar installed a triangulation station marker in 1970.¹⁴ I was unable to locate any documentation on these markers, so I can’t say whether or not the replacement of the border monument was associated with the survey marker installations.

1. This was at the end of a nine-week trip to Chile for telescope repair and maintenance work. Traveling during the COVID-19 pandemic, even with an N95 mask and PCR tests, was a nightmare, particularly for the flights in the United States, and I would not have done so if the repair work wasn’t necessary.  ↩

2. This was the earliest we could leave, since the COVID-related curfew ended at 5 am. However, leaving earlier would have involved more driving off-road in the dark, which is less than ideal.  ↩

3. An alternative turn-off at kilometer 144.4 can also be used.  ↩

4. This is consistent with what was communicated to me via my colleagues from the local tour guides they know.  ↩

5. The track was extremely rutted on the steep slope, and I would highly recommend using 4L for this to avoid having to maintain higher speeds to maintain engine power.  ↩

6. Per satellite imagery, the track continues on and crosses the Bolivian border.  ↩

7. Heading directly toward the summit would have been a much steeper and more difficult route.  ↩

8. I attempted to use photogrammetry to reconstruct a 3D model of the summit using drone footage from a Chilean TV show. Unfortunately, the low-quality video frames combined with a lack of orbiting shots led to a failed reconstruction. I didn’t bring my DJI Mavic Mini to take my own photos for photogrammetry, since it can’t handle the high altitude (it barely flies at ~5200 m without any wind).  ↩

9. We considered stopping at the lake on the way down but decided against it, since it would have involved an additional uphill climb to return from it.  ↩

10. These vicuñas were far more skittish than the vicuñas found along the Jama road or on Cerro Toco.  ↩

11. Informe Final De La Comision Mixta Demarcadora De Limites Argentina–Bolivia. Buenos Aires: Talleres Gráficos del Instituto Geográfico Militar, 1953.  ↩

12. La Frontera Argentino–Chilena: Demarcación General, 1894–1906. Buenos Aires: Talleres Gráficos de la Penitenciaria Nacional, 1908.  ↩

13. A detailed photo of a different monument in the same publication shows that the actual monuments matched the drawing.  ↩

14. I did not find any markers from Argentina.  ↩

I also took a 360 degree panoramic timelapse as well as a near-infrared timelapse. Unfortunately, the Ricoh Theta S recording the panoramic timelapse stopped recording during totality, and I wasn’t able to fit the sun in the frame of the near-infrared timelapse.

The trail to the summit is easy to discern. It does split in a few places, but as long as one keeps heading towards the summit, it is difficult to become lost.¹ An elevation profile derived from my GPS track is below. It is approximately 1.7 km to the summit, with around 360 m of vertical gain (average grade of 22%). Round-trip, the climb took a little over two hours.

From the summit, one has an excellent view of Licancabur, Juriques, and Boliva to the north; Argentina to the east; and ALMA to the southwest.

1. There’s no vegetation to obstruct one’s view.  ↩