Wednesday, January 4, 2023

Northernmost U.S. Glacier

This is a bit off-topic for this blog, but I came across an interesting piece of news that's tangentially related to Alaska climate: Zachary Sheldon of the Valdez-based Alaska Guide Co has documented the existence of a previously (formally) unrecognized glacier to the north of the Brooks Range, in the Shublik Mountains.  It's only 30 miles from the coast.

https://www.adn.com/alaska-news/science/2022/12/26/a-wilderness-guide-stumbled-upon-alaskas-northernmost-glacier-one-not-marked-on-any-map/

At 69.5°N, this is the northernmost glacier in the USA.  Courtesy of Google Maps, the red marker below shows the location (click to enlarge):

Thinking about summer temperatures, the elevation of about 4400 feet is similar to the Atigun Pass SNOTEL site (4800'), but Northernmost Glacier (as named by Zachary) is considerably farther north and closer to the ocean.  So I'd guess that summer temperatures are lower than at Atigun, where the July mean temperature is ostensibly around 46°F (I'm not sure about SNOTEL instrument bias in summer).  We also know that the Utqiaġvik radiosonde measurement averages about 40°F in July at 850mb, or 4700' above sea level.

Zooming in (see below), it's pretty clear that the glacier is in favorable circumstances: surrounded by peaks on all sides, it is sheltered from the shallow Arctic sunlight for many hours of the day.  The Google Maps terrain layer indicates that the ridge to the south and west rises more than 1000 feet in a horizontal distance of 2000 feet or so, which means the sun must be higher than about 25° above the horizon to shine directly on the center of the glacier.  Subject to cloudiness, this can happen for about 10-11 hours of the day at the summer solstice, but obviously much less for most of the year.


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