New Weather Stations Aid Denali Researchers and Climbers

New weather stations provide live updates of conditions on Alaska’s Denali, the tallest peak in North America. The weather stations sit atop the mountain on the Kahiltna Glacier and provide important weather information for climbers and scientists alike. They allow scientists to track snowpack and provide the climbing community with a better sense of weather conditions on the 20,310 foot mountain.

Michael Loso, a National Park Service geologist, started the project in order to better understand weather patterns at higher altitudes. GlacierHub spoke with Loso to get a better understanding of the project and its impacts.

GlacierHub: How do these new weather stations on Denali help climbers and help researchers assess glacial retreat?

Mike Loso: We’ve established three new weather stations in the accumulation zone of Denali’s Kahiltna Glacier. These stations, at approximately 7,000, 10,000, and 14,000 feet, continuously measure air temperature and snow accumulation and melt on a year-round basis. In addition, the highest and lowest stations measure wind speed and direction, incoming and outgoing solar radiation, and send those measures via satellite telemetry back to publicly available servers on a continuous basis. They provide critical information for mountaineers, for weather forecasters, and for National Park Service climbing/rescue rangers. The fact that two of these stations are providing regular, real-time, hourly, year-round weather information means that climbers can plan their trips wisely.

Glaciologists like me use the data from these stations to understand the year-round patterns of snow accumulation and melt, and to compare those measurements with existing measurements we have been making for decades at lower elevation sites on the Kahiltna. Together, all these measurements allow us to measure not only the net shrinkage of Kahiltna Glacier, which is ongoing, but more importantly to understand how that shrinkage is controlled by the detailed changes in our climate.

GH: How are these measurements different than how researchers typically observe a glacier’s status?

ML: Most glacier mass-balance studies have traditionally focused on glaciers that are fairly small, or in the cases of larger, higher-elevation glaciers they favor measurements in the lower elevations. There are very few studies of snow accumulation and melt at high elevations of large glaciers because it is too difficult to install and maintain on-glacier weather stations in such inhospitable environments. But those high elevation sites are usually the very places where most snow accumulation occurs, even in the summertime during what would be considered the “melt season” at lower elevations. So glaciologists still have uncertainty about year-round patterns of snow accumulation, and the only way to measure that is to measure it continuously. But that’s difficult. If you place the weather station on a rocky outcrop near the glacier, then you are definitely not getting a “true” signal of snow accumulation because rocky outcrops are by definition wind-scoured and atypical of the glacier’s accumulation zone. If you place a normal weather station on the glacier itself, it will promptly get buried by ongoing snow accumulation. So our strategy is to place the stations on very tall masts that are anchored in the glacier surface and then to periodically dig the stations out and “reset” them when the snow threatens to bury the existing station. We couldn’t accomplish this without a lot of logistical support, and that is possible on Denali only because of the substantial operation run by the National Park Service mountaineering rangers. They establish and maintain rescue camps at 7,000 and 14,000 feet on the Kahiltna Glacier, and their presence (along with the aviation assets required to support that operation) allow us, in partnership with them, to maintain these stations.

GH: What makes the Denali glacier unique in terms of climate change?

ML: Denali is the tallest mountain in North America, and it is located in a fairly high latitude, by US standards. So the top is a really cold place, even by the standards of most glaciers. That cold (and windy) climate results in patterns of snow accumulation and snow and ice melt that are not typical of most glaciers in the US. typically glaciers accumulate more snow as you go higher with maximum accumulation near the summit. But anecdotal observations suggest that this pattern does not apply at Denali. Instead, it appears that snow accumulation is actually highest at the mid-elevations of the Kahiltna Glacier and that snowfall diminishes as you go higher. That’s unusual, and is probably due in part to the inability of very cold air to hold much moisture. Interestingly, some of our colleagues recently published findings that snow accumulation rates on nearby Mount Hunter appear to have actually increased over recent centuries. We hypothesize that some of that increase may be due to the enhanced ability of warmer air to hold and then release moisture—a process that might lead to more snowfall on the Kahiltna Glacier as climatic warming continues. Our data will allow us to test this intriguing hypothesis.

GH: Are there any other parks that are using these types of weather stations

ML: Some of the technology (sensors, power supply, data-loggers) are in common use, but this particular application in a high-glacier, snow-accumulation environment is not presently being done anywhere else that we’re aware of. That said, similar designs have been applied sporadically in the past, and we have benefitted from lessons learned during those experiences.

Scientists Pam Sousanes, Dom Winski, and Michael Loso program a Denali weather station. (Source: National Park Service/Tucker Chenoweth)

GH: What inspired the project?

ML: In addition to the desire to understand glacier environments better, to better predict mountain weather, and to provide real-time information for climbers and rescue rangers, I was especially motivated to tackle this project by my own history on Denali. Fresh out of college I worked for a couple seasons as both a guide and a mountaineering ranger on Denali, and then over the subsequent 20 plus years I’ve stayed involved there as a volunteer rescue patrol member, as a scientist, and as a recreational skier and climber. Through those experiences, I’ve come to know the mountain well, but also many of the long-term professionals working on the mountain (guides, rangers, pilots). So I’ve come to really love the place and to have a fairly broad knowledge of the scientific and societal challenges posed there by climate change. In light of all that, this project really excited me and continues to be a pleasure to work on.

GH: What does the future look like for this technology?

ML: The technology itself is not anything unusual. We are just deploying that technology in a somewhat unusual way and place. I would call our work experimental, in the sense that we expect to see challenges and damages related to the extreme climate. But as we learn from those failures, I would expect that we will capitalize on opportunities to apply this technique in other places.

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No-Fly Zone Administered Over Glacier Crash Site

In 1952, a military plane crashed into Mount Gannett, 50 miles east of Anchorage, killing all 52 service members on board. The plane was located in 2012 at Colony Glacier, but it has taken years to retrieve the remains as rescuers can only travel to the crash site in June, when conditions are safest on the glacier. Over this time, the receding glacier has made the crash site more visible, but it has also enticed sightseers on helicopters, who risk disturbing the remains or removing artifacts. As a result, a no-fly zone has been administered this month by the Federal Aviation Administration to stop people from disturbing the crash site.

To date, 35 human remains have been repatriated, but it may take several more years to retrieve the remaining 17. The plane went down in the Chugach Mountain range, one of the snowiest locations in Alaska. During the winter of 1952-1953, in the Chugach’s Thompson Pass, a record 81 feet of snow was recorded. Colony Glacier remains dangerous due to deep crevasses, variable weather and sharp pieces of ice.

Erin Pettit, an associate professor of glaciology at the University of Alaska at Fairbanks, told GlacierHub about similar plane crashes that have been buried beneath glaciers. “There are a handful around the world – at least one in Greenland and one in Antarctica. Sometimes they weren’t ‘lost’ in the sense that no one knew what happened, but they just couldn’t extract the plane,” she said. “The plane was absorbed by the glacier and won’t re-emerge for hundreds or even thousands of years, depending on where it landed and how big the glacier is.”

When a plane crashes into a glacier, it is covered by snowfall and over time freezes into the glacier. When the glacier moves downslope, the plane moves along with it, until it is later revealed at the front of the glacier. Warmer temperatures speed this process up.

Flowpath of Colony Glacier (Source: Bob McNabb).

Bob McNabb, a glaciologist at the University of Alaska, calculated the speed and trajectory of the flowpath of the Colony Glacier and made a map for GlacierHub. Using a back-of-the-envelope calculation, McNabb said the plane traveled 23 kilometers along the flowpath, which means it would have traveled one meter per year. Using this analysis, which involved the use of satellites, McNabb calculated that the average surface velocity would have been about 1.5 meters per year.

Michael Loso, a physical scientist at Wrangell-St. Elias National Park and Preserve, told GlacierHub that Colony Glacier has a velocity of about 3 feet per day, saying, “That’s fast but not unreasonably fast for a big Alaskan glacier.”

Alaska has a higher rate of plane crashes than the rest of the United States for reasons like frequent inclement weather, jagged terrain, which can be obscured by clouds, and the fact that flying is the only way to get to certain remote places. The cause of the 1952 crash has never been determined.

Loso added that such crashes at glaciers are not that uncommon, saying, “Many glaciers are in mountains, and planes run into mountains every once in awhile.”