Forecast for the Logan Area Mountains

Toby Weed
Issued by Toby Weed for
Monday, January 28, 2013

There is a CONSIDERABLE (or level 3) avalanche danger in the backcountry today. Dangerous avalanche conditions exist in places, and triggered persistent slab and wind slab avalanches are likely on drifted mid and upper elevation slopes, especially in areas that picked up significant accumulations of heavy new snow yesterday. Some natural activity is possible in these areas. Heightened conditions exist, avalanches are possible, and there's a MODERATE (or level 2) danger on most other slopes. Avoid and stay out from under steep slopes with significant accumulations of new and/or drifted snow. Careful snowpack evaluation, cautious route-finding, and conservative decision making will be essential in the backcountry today.

Heavy snowfall and strong west winds overnight will create a rising danger, and very dangerous avalanche conditions may develop in some areas by tomorrow morning.

Low
Moderate
Considerable
High
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Avalanche Watch

Avalanche Watch for the Logan Area Mountains: Heavy snow and strong winds are overloading slopes with poor snow structure at all elevations. Continued snowfall and strong wind overnight could create a HIGH avalanche danger in the backcountry, with natural and human triggered avalanches becoming likely on many slopes. Avoid and stay out from under steep slopes and obvious or historic avalanche paths....

Weather and Snow

The Tony Grove Snotel at 8400' reports 5 inches of new snow from yesterday. It's 11 degrees, there is 53 inches of total snow, and 65% of average water content for the date. As of 11:00 last night, the Ben Lomond Peak Snotel reported 9 new inches, with 1.3 inches of water equivalent. The 9700' CSI Logan Peak weather station reports a chilly 4 degrees and overnight northwest winds averaging in the lower single digits. You'll find rather heavy new snow and heightened avalanche conditions on most slopes in the backcountry, with dangerous conditions and triggered avalanches likely in areas that picked up more snow... The danger will rise and become more widespread overnight and tomorrow with significantly more snow and intensifying west winds forecast....

Recent Avalanches

A rider triggered a good sized soft slab avalanche in Miller Bowl, south of Tony Grove Lake Friday afternoon. The 200' wide by around 14" deep avalanche released below the rider as he was side-hilling on a steep north facing slope at around 8600' in elevation. Nobody was caught. A natural wet avalanche cycle occurred in the past few days at lower elevations in Logan Canyon, with loose wet avalanches hitting the Logan River several times, the Logan River Trail, and Hwy 89 in the Temple Fork and Dugway areas.

Here's a link to our updated avalanche list...

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Avalanche Problem #1
New Snow
Type
Location
Likelihood
Size
Description

Avalanches will likely fail 1 to 2 feet deep on very weak faceted snow created during the drawn-out January high pressure systems. Areas plagued by the shallowly buried January 8 rime-crust , which is intact and fairly widespread in the region, and weak faceted snow associated with it are most suspect. The preexisting snow on shady mid elevation slopes is especially weak, and avalanches could occur in unexpected areas on slopes approaching or steeper than 35 degrees. Heavy snowfall and strong winds overnight and tomorrow are likely to add significant weight to the fragile snowpack, and the danger of persistent slab avalanches will increase accordingly. Dangerous avalanche conditions already exist today in some areas with significant accumulations from yesterday's storm. In these conditions you could trigger avalanches remotely, from a distance or worse, from below. Recent avalanches, audible collapsing, and cracking are red flags indicating instability...

Avalanche Problem #2
Persistent Weak Layer
Type
Location
Likelihood
Size
Description

Triggered wind slab avalanches around one-foot -deep are possible on drifted upper and mid elevation slopes. Watch for and avoid stiffer fresh wind slabs on the lee side of major ridges and in and around terrain features like cliff bands, sub-ridges, gullies, and scoops. Potential wind slabs are drifts that often appear smooth or rounded and chalky looking, and they sometimes sound rather hollow. Intensifying winds from the west-southwest overnight and tomorrow, along with predicted heavy snowfall will cause the danger of wind slab avalanches to increase further. Cracking and audible collapsing are red flags, and reevaluation of your route is recommended if you encounter these conditions.

Additional Information

The National Weather Service has issued a Winter Storm Warning for the mountains in our area through early Thursday morning. Snow is likely today, mainly in the afternoon, with a couple inches of accumulation possible by evening. High temperatures in the mountains will be around 20 degrees in mid-morning before dropping into the mid teens in the afternoon. It'll be cloudy with a moderate west wind. Intensifying westerly winds and snow are expected tonight, with 4 to 8 inches of accumulation possible by tomorrow morning. Tomorrow looks quite stormy, with strong west-southwest winds and 7 to 11 inches of additional snow accumulation forecast. More snow is expected on Wednesday High pressure conditions are expected to return to the region late in the week....

Check out the new Logan Mountain Weather page...

General Announcements

Remember your information from the backcountry can save lives. If you see or trigger an avalanche, or see anything else we should know about, please send us your snow and avalanche observations. You can also call us at 801-524-5304 or email by clicking HERE. In the Logan Area you can contact Toby Weed directly at 435-757-7578.

I will update this advisory on Monday, Wednesday, Friday, and Saturday mornings by around 7:30...

This advisory is produced by the U.S.D.A. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist.