Logan Avalanche Advisory

Forecaster: Toby Weed


Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)

Danger Rose Tutorial

There is a level 3 or Considerable danger in the backcountry around Logan. Dangerous avalanche conditions exist, and triggered fresh wind slab or storm snow avalanches are probable on steep drifted slopes at upper elevations.. I expect things to become more stable fairly rapidly and the danger to diminish throughout today, dropping a notch to level 2 by this evening. Although mostly cemented in place by a solid layer of rime, dangerous persistent slabs are still possible and might be triggered at upper elevations on slopes that did not recently slide. Careful snowpack evaluation, cautious route finding, and conservative decision making are crucial in upper elevation avalanche terrain today.


Just in time, overnight snowfall rescued us from horrendous crusty snow conditions... I found rough riding on the drainage-gully-striped and ice-crusted lower and mid elevation snow in Franklin Basin yesterday... The snow was a bit nicer, smooth and quite supportable up higher, but a very destructive windy ice storm over the weekend toppled trees and tossed branches all over the place in Steep Hollow.... There are also extensive piles of recent avalanche debris to contend with, especially on and under steep treed slopes. The 8400' Tony Grove Snotel reports around 8 inches of heavy new snow with 1.3 inches of water, mostly from early this morning. It's 23 degrees currently, and there's 93 inches of total snow at the site containing 161% of average water for the date. The Campbell Scientific weather station at 9700' on Logan Peak reports a still rimed wind sensor and 17 degrees.


The wet, warm, and windy weather over the weekend spawned an extensive natural avalanche cycle in the region....

See our avalanche list


      Over the next 24 hours.

The heavy and drifted storm snow from overnight might not stick very well to the underlying ice/rime crust initially, but I expect a fairly rapid increase in stability today... Although unrecorded, mountain top southwest to northwest winds were in the 20 to 35+ mph range overnight, certainly strong enough to form sizable fresh wind slabs on the lee sides of ridges and sub-ridges and in terrain dictated deposition areas, like under cliff bands, around rock outcroppings, along gully walls, or in scoops or depressions..... Also, remember that more drifting occurs near saddles or passes since constricting terrain forces increased surface winds....


      Over the next 12 hours.

Heightened avalanche conditions exist at upper elevations where a substantial slab rapidly built up on slopes with buried weak layers over the weekend.. Although I'm thinking your weight will have little affect through the concrete-like rime crust, triggered persistent slabs, 2 to 3 feet deep, are still possible today at upper elevations, and dangerous avalanches might be triggered on some steep slopes that did not slide during the recent ice storm.


A few more inches may fall this morning, but the mountains are now under a northwest flow, and precipitation should mostly shut down soon... Expect clearing conditions in the mountains today, with 15 mph northwest winds and temperatures in the upper teens. With clear skies,overnight temperatures will drop into the single digits. A high pressure system will control the weather through the end of the week, and the next somewhat dry looking storm will be upon us as we head into the weekend...


You can view a photo summary of last year's avalanche activity in the Logan Area HERE

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I will update this advisory in the mornings on Mondays, Wednesdays, Fridays, and Saturdays, and on other days if backcountry avalanche conditions warrant...

You have the opportunity to participate in the creation of our own community avalanche advisory by submitting avalanche and snow observations. You can also call us at 801-524-5304 or Toby at 435-757-7578, or email by clicking HERE

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This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

This information does not apply to developed ski areas or highways where avalanche control is normally done.  This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

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