Logan Avalanche Advisory

Forecaster: Toby Weed

BOTTOM LINE

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


Danger Rose Tutorial

There's a CONSIDERABLE (3) danger in the backcountry around Logan. Triggered wind or persistent slab avalanches 1 to 2 feet deep are likely on slopes steeper than around 30 degrees, and some naturals are possible in steep upper and mid elevation terrain, especially on sunny slopes during the heat of midday... Very dangerous and much bigger deep slab avalanches are still possible on steep slopes plagued by weak sugary snow near the ground... These are probably getting very difficult to trigger in most areas, but are most possible on upper and mid elevation slopes with generally shallow snow cover.

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


CURRENT CONDITIONS

Don't let today's nice weather affect your better judgment. This is no time to let your guard down. Keep in mind that most avalanche accidents occur when there is a Considerable danger, and a "bluebird powder day" right after a storm is perhaps the most common weather/human-factor scenario in avalanche accidents...

The Tony Grove Snotel reports around 6 inches of new snow and 8/10ths of an inch of water accumulation in the last 48 hours, with most of this coming on Wednesday. There's now 76" of total snow on the ground containing 70% of average water for the date. Its 13 degrees at the 9700' Campbell Scientific--Logan Peak weather station and the wind sensor is likely rimed, but showing a north wind direction.


RECENT ACTIVITY

It was a wild day in the Wasatch Backcountry with numerous natural and easily triggered avalanches reported to the Utah Avalanche Center...

Quieter locally; with no activity reported from the Logan Area since Monday, when a skier triggered a foot deep slab that broke just below his party on a northwest facing slope at around 8200' in upper Green Canyon...

Here's an updated local backcountry avalanche list:


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

A weak layer consisting of feathery frost crystals or surface hoar, buried and preserved by light snowfall on February 10th, is widespread across the region. This has been producing numerous triggered and natural avalanches since it was buried and even fairly minor additional snow loads seem capable of reactivating the weakness. Many recent triggered avalanches occurred on less steep than expected slopes. Slope angle estimates from these reported avalanches commonly range from 30 to 35 degrees. Today's likely persistent slab avalanches might not be as manageable or forgiving as last week's. Fairly strong and sustained southwest winds will continue to build stiff drifts in exposed terrain, and fresh wind slabs could be dangerously sensitive and somewhat solid...You might trigger a dangerous avalanche from a distance or from below.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Weak sugary or faceted snow near the ground is notoriously slow to heal, and recent natural deep slab activity in the zone proves that a brood of dragons is still hanging around. I'm particularly concerned by huge recent natural deep slab avalanches on upper elevation east and west facing slopes in the Mount Naomi Wilderness.. Cougar Peak South Fork of High Creek

Although the danger of deep slab avalanches is gradually diminishing, direct solar warming or green-housing today could cause increased slab creep rates or slab softening and reactivate the deep weakness in some areas.. Triggered deep slab avalanches could step down to weak snow near the ground and be very broad and destructive. Deep slab avalanches might be initiated from a shallower area on the slab, so watch out for steep rocky or terrain with generally shallow snow cover.


THREAT #3

WHERE PROBABILITY SIZE TREND
      Over the next 10 hours.

Despite breezy conditions, expect fairly significant solar heating today. This may lead to a danger of wet avalanches on steep slopes, especially on slopes with fresh snow that are exposed to several hours of direct sun.


MOUNTAIN WEATHER

Expect mostly fair, but breezy and warmer weather in the mountains as a high pressure system controls today's weather. Mountain temperatures should climb into the mid thirties, with a fairly strong and sustained southwest wind also forecast. A splitting storm will swing through the region tomorrow affecting mainly the southern mountains, but there should be enough moisture for a couple inches of accumulation in our area...

A high pressure will build and the atmosphere will dry out early next week, with the next potential storm coming around Wednesday...


GENERAL ANNOUNCEMENTS

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

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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 Saturday 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.