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 April 11, 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 April 11th at 10:00 pm.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Backcountry Access Inc

Current Conditions:

Temperatures are still way above freezing at 8500', and any re-freeze at mid-elevations won't be very deep.  Only a couple inches of wet snow fell yesterday and last night at the highest elevations, while rain fell up to about 7500' today.  Cooler temperatures last night put a supportable crust on most slopes, but the underlying snow in a lot of areas is still soft and saturated.  I was able to ride just about anywhere today, and I found decent dust-on-crust turning conditions, especially on upper elevation southerly facing slopes, which sported a solid sun-crust under a couple inches of new snow.

Snow and Avalanche Conditions:

Spring is here, and the water is starting to come on down from the hills.  There's 58 inches of water contained in the snow at the Tony Grove Snotel site, which is 150 percent of normal.  The local rivers and side-streams are starting to flow with spring runoff, and I've noticed the water-level in the Logan rising each day since last week.  We've been noticing runnels or mini natural drainage ditches developing in the snowpack on many slopes, which is a good sign.  It means the snow's internal plumbing is working, and melt-water is escaping in a controlled way.  

A steady southwest wind and cloud cover will keep a lid on the warming, and many slopes may not soften up enough to present much of an avalanche problem.  But some sheltered sunny or shallow slopes, especially at mid-elevations, may soften up to the point where wet avalanches will become possible.    Solar heat may be trapped in the atmosphere by clouds and the heat could be amplified just like it is in a greenhouse.  You'll know when wet avalanches are possible when you start sinking through the surface crust into mushy snow underneath it.  Basically, if it feels hot to you and the snow gets soft and wet, It's time to leave the steep slopes.  You should give monstrous sagging cornices and widening glide cracks lots of respect and space, especially in the heat of the day.  Glide avalanches are possible this time of year any time of day or night on particular slopes with smooth ground or rock surfaces, which become lubricated by melt-water. (more glide photos)

Bottom Line:

Warmth will cause the danger of wet avalanches to rise to MODERATE on some slopes steeper than about 35 degrees in the backcountry.  The danger will be greatest on sheltered sunny slopes at lower and mid-elevations, but you might trigger an avalanche on any steep slope with warmth-softened and saturated snow.

Mountain Weather:

We're in for a couple more warm days in the mountains, but increasing winds should keep at least exposed areas ventilated.  The heat will peak on Thursday and overnight re-freezes will be minimal. The next Pacific storm will roll into the region on about Friday night

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 Wednesday night. I will update it again Thursday evening.  Sunday April 16th will be our last regularly scheduled advisory.

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.