Wasatch-Cache National Forest  In partnership with:  Utah State Parks and Recreation, Friends of the Utah Avalanche Center-Logan, and Utah State University College of Natural Resources.

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Logan area Avalanche advisory

Tuesday February 28, 2006

Hello, this is Toby Weed of the Forest Service Utah Avalanche Center with your Logan area backcountry avalanche and mountain weather advisory.  It's Tuesday  February 28th at 9:00 pm.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from avalanchetools.com.

Current Conditions:

Strong and warm southwesterly winds blasted the mountains today, accelerating the preliminary melt-down and turning low elevation trails into running streams and mud-holes.  At one point this afternoon, as I climbed onto an exposed ridge, a burly gust of wind nearly stole the windshield right off my sled. The Campbell Scientific weather station on Logan Peak recorded sustained average southwest winds in the 40 to 45 mph hour range.  The station doesn't record gusts, which were much higher--almost knocking me down a few times.  Rain, wind, and a few days of spring-like warmth turned the snow even at fairly high elevations into a soggy mess, and looking at it today, I was soaked before the rain even began to fall.  As of this writing, the Snotel site at Tony Grove has picked up 1.4 inches of water from the storm with about 9 inches of heavy snow.  The winds on Logan Peak shifted and diminished with frontal passage this evening, and they're now coming from the northwest, averaging about 15 mph.  Temperatures dropped as the cold-front moved in, and the slush under this evening's blanket of Sierra-like snow will gradually solidify.

 Snow and Avalanche Conditions:

 I didn't see much snow drifting around today in the tempest at upper elevations because of the already scoured-to-the-bone and moist surface conditions. But I noticed suspicious looking solid drifts or hard slabs on lots of upper elevation steep north and east facing slopes.  Some are sitting on intact  weak layers made up of sugary or faceted snow and could be in a fragile state of balance, just waiting for you to come along to trigger an avalanche.  These drifts will be invisible on Wednesday, hidden under tonight's new snow.  Although the wind is subsiding tonight with the onset of snowfall, it's still plenty strong enough to build fresh drifts with the new snow.  These new soft slabs are building up tonight on lots of steep slopes across the region, and they may present a widespread avalanche problem in the morning.  The huge cornices are building up as well tonight, and they could be quite sensitive--likely triggers of slab avalanches below.

You could trigger soft slab avalanches consisting of new snow on many wind-drifted slopes in the region, and there are a few places where you might trigger a more dangerous hidden hard slab.  You'll find most of the fresh drifts above about 7500' on slopes facing northeast through south and the hidden hard slabs above about 8500' on slopes facing north, northeast, and east. Some natural avalanches could run overnight, but they'll be less likely on Wednesday since the storm and the wind will be gone by morning.  The saturated snow at lower and mid-elevations will start to freeze up with the cooler temperatures, but seasonal solar warming of the new snow could cause loose wet avalanches on steep sunny slopes around midday.

Bottom Line:

There's a CONSIDERABLE danger and you could trigger avalanches on numerous upper elevation wind-drifted slopes steeper than about 35 degrees in the backcountry.  There's also a MODERATE danger and avalanches are possible at mid and lower elevations and on other steep slopes with significant deposits of heavy new snow.  Solar warming in the heat of the day may cause a MODERATE danger of wet point-release avalanches on steep slopes with saturated surface snow.

Mountain Weather:

The National Weather Service's Winter Storm Warning will expire early Wednesday morning and the storm will be well east of the region by dawn.  Under partly cloudy or mostly sunny skies, Wednesday's weather will be completely opposite from today's.  The winds will be light, although they'll swing back around  from the south and start to increase in the evening as the next storm approaches.  Thursday should be cloudy, warm, and windy once again, and a vigorous storm is still on track for late Friday.

General Information: 

If you're confused by some of our avalanche terms check out the cool new Avalanche Encyclopedia. 

For a list of recent avalanches in  the regional backcountry go to Avalanche List.  Snow nerds, check out the new Snow Profiles page.  Check out our Images Page for pictures of recent local avalanches.

Please send backcountry observations to [email protected] or leave a message at 755-3638, especially if you see or trigger an avalanche in the backcountry. We really want to hear from you, even if you think your observation is unimportant.    The information you provide may save lives...

This advisory will expire on Wednesday night.  I will update it again Thursday evening.

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. 

National Weather Service - Salt Lake City - Snow.