Logan Avalanche Advisory

Forecaster: Toby Weed

SPECIAL ANNOUNCEMENT

A Special Avalanche Advisory continues for all the mountains of Utah today. Large avalanches can still be triggered by people on slopes approaching 35 degrees. These avalanches are responsible for two fatalities this week. A very persistent weak snowpack will remain unstable for some time to come. People should continue to avoid steep avalanche terrain this weekend.


BOTTOM LINE

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


Danger Rose Tutorial

Avalanche conditions are still very dangerous in the backcountry around Logan. There is a CONSIDERABLE (3) danger, and you could trigger a deadly hard slab avalanche 2 to 5 feet deep or deeper and potentially quite wide in steep upper elevation terrain with preexisting weak snow, and on slopes that didn't already recently avalanche. In these conditions, you might trigger avalanches from a distance, or worse, from below. You should avoid travel on or below such slopes, as recent avalanches in the region have been running far, many to the fullest extent of their paths.

Careful snowpack evaluation, cautious route finding and conservative decision-making are essential for safe backcountry travel today.


CURRENT CONDITIONS

With 60 inches of total snow on the ground and no new snow to report, the Tony Grove Snotel site now sits at 57% of normal water content for the date... It's 21 degrees at the 9700' Campbell Scientific weather station on Logan Peak, and a gradually increasing southwest wind, currently averaging a bit over 20 mph...


RECENT ACTIVITY

Huge, long running natural hard slab avalanches from last weekend several feet deep are visible from the air across the Logan forecast zone, several half-a-mile wide or wider. Most activity occurred on northwest through east facing slopes, with a couple notable exceptions on southeast west facing slopes. I will continue to post our aerial observations from 1-28-10 here

Numerous natural and a couple triggered avalanches occurred recently in the region, one closing down both lanes of Logan Canyon Highway in the middle of the day on Sunday. We had a close call on Wednesday (1-27-10) up above Tony Grove, just north of Naomi Peak, when a snowmobiler unintentionally triggered a large hard slab avalanche, which propagated behind him. It was a good thing the rest of the sledders in the well prepared party were watching from a safe location... ..We've been able to photograph and visit a few, and we're still compiling reports... If fact, 2010 is so-far quite an active year for avalanches in the backcountry around Logan..

.Here's an updated local backcountry avalanche list:


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Last weekend, heavy and drifted new snow overloaded slopes plagued by existing weak sugary layers, and a very widespread natural hard slab avalanche cycle occurred across the Logan Forecast Zone. This weekend's storm might add enough weight to reactivate deeply buried weak layers.

Deep slab avalanches are still probable in steep upper and mid elevation terrain that didn't recently avalanche. Triggered deep or hard slab avalanches could step down to weak snow near the ground and be very broad and destructive. Smaller avalanches overrunning slopes with deeply buried weak snow could produce a much larger and more dangerous avalanche, and you still might trigger a dangerous avalanche from a distance or below.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 36 hours.

A storm beginning tonight and lasting through Sunday could bring a decent shot of fresh snow...This will cause a general upswing in avalanche danger and complexity, with wind slab and storm snow avalanches becoming more likely with higher accumulations and/or sustained winds.


MOUNTAIN WEATHER

Southwest winds are gradually picking up this morning on Logan Peak and the inversion should break up today as the next Pacific Storm moves into the region. It's looking like tomorrow's storm may favor the Northern Wasatch and Bear River Ranges with a moist southwest flow and a pool of cold air moving through southeast Idaho...Preliminary National Weather Service forecast calls for 9 to 17 inches of accumulation between overnight tonight and late Sunday night in the Bear River Range.


GENERAL ANNOUNCEMENTS

I will be issuing morning avalanche advisories for the Logan area on Mondays, Wednesdays, Fridays and Saturdays.

Consider purchasing some Beaver Mountain lift tickets here from our good friends at Backcountry.com in partnership with Ski Utah. All proceeds benefit the Friends of the Utah Avalanche Center.

If you want to get this avalanche advisory e-mailed to you daily click HERE.

Send us your avalanche and snow observations. You can also call me at 435-757-7578 or the SLC office at 800-662-4140, or email to uac@utahavalanchecenter.org

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

I will update this forecast Monday morning. Thanks for checking in....


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.


This advisory provided by the USDA Forest Service, in partnership with:

The Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Division of Emergency Management, Salt Lake County, Salt Lake Unified Fire Authority and the friends of the La Sal Avalanche Center. See our Sponsors Page for a complete list.