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Logan area Avalanche Statement

7:30, Saturday April 19, 2008

Hello and good morning, this is Toby Weed of the Utah Avalanche Center with your Logan Area backcountry avalanche and mountain weather advisory.  It’s Saturday April 19th, at 7:00 in the morning.  Today’s avalanche statement is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from you….  

Current Conditions:

It’ll be warm and very windy in the mountains today, ahead of a Pacific cold front that will arrive tonight and bring some snow for tomorrow.  Overnight temperatures stayed above freezing at most mountain stations and the refreeze of yesterday’s saturated surface snow is marginal at best.  Surface crusts that formed overnight will quickly loose strength after exposure to powerful high angle spring sun possible this morning or greenhouse warmth. 

We were surprised to find pretty nice settled powder and smooth conditions on upper elevation north facing slopes yesterday and reasonably solid and supportable snow on mid and lower elevation slopes. It is currently 42 degrees at The Tony Grove Snotel, and with 88 inches of total snow, the station sits at 106% of average water content for the date. 

Avalanche Conditions: 

We’ve had a fairly quiet week avalanche-wise locally, with no significant avalanches reported or observed since last weekend’s wet cycle spurred by the very warm temperatures.  Several inches of new snow fell on the warmed and then refrozen snow on Tuesday and Tuesday night at upper elevations, and this bonded well.  We couldn’t get anything to budge yesterday, even on the steepest drifted slopes we could find.

Today’s southwest wind will be strong enough to build stiff drifts and wind slabs in exposed upper elevation terrain and near ridge-tops.  During and for a little while after tomorrow’s forecast spring storm, shallow soft wind slabs consisting of new snow will likely be our biggest concern.  The sensitivity or likelihood of triggering these will depend on how well the new snow bonds to the warm or crusty stuff that’s now on the snow surface…Huge local cornices will build with the wind and become more sensitive or active with the heat today.  As a good general rule, you should avoid and stay out from under them this weekend.

Solar warming from the intense high angled spring sun, (if it pokes out through the clouds even for a short time), and a warm southwest wind will cause last week’s new snow to quickly become saturated and prone to wet avalanching on some steep slopes.  I’d expect to see wet activity limited to point-release type avalanches involving the newer snow.  Wet avalanches will continue to be possible on steep slopes with saturated snow (especially when fresh) throughout the inevitable spring melt down.

 

Bottom Line: 

  We have stopped issuing danger ratings for the season.   But, as long as there is snow on steep slopes in the backcountry avalanches will continue to be possible, especially during or right after windy spring storms or prolonged warm spells.

Mountain Weather:

It will be quite warm and windy today in the mountains with a southwest wind typical before storms from the northwest.  A cold front will pass over the region late tonight with snowfall when the cold air arrives late.  Another cold front is possible around mid-week…..

General Announcements: 

Check out the images page for photos of some of this season’s avalanches.

Go to the Avalanche Encyclopedia if you have any questions about terms I use in the advisory.

I'm very interested to know what you're seeing out there.  Please e-mail observations to me at [email protected] or leave me a message at 755-3638, especially if you see or trigger an avalanche in the backcountry. We keep all observations confidential.

I will update this advisory next weekend or intermittently if conditions warrant. 

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.