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

Thursday March 2, 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 Thursday  March 2nd 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 Backcountry Access Inc.

Current Conditions:

The mid and lower elevation snow is still sopping wet from the warmth and rain earlier in the week, but you can find nice shallow powder conditions on upper elevation northerly facing slopes.  Temperatures will drop below freezing in the mountains tonight, and the low elevation isothermal slush should further solidify.  Strong southwesterly winds will find some snow to drift around at higher elevations on Friday, and clouds will stream in ahead of a fast-moving storm, which will move over  the region  Friday night.

  Snow and Avalanche Conditions:

 A wet point-release avalanche closed Highway 89 in Logan Canyon for little while on Tuesday afternoon after rain soaked the already saturated low elevation snow.  Freezing temperatures last night froze the upper couple inches, but by this afternoon you would sink to the ground in mush in lower elevation meadows.  We'll see the same situation on Friday, and there may be some very steep sunny mid or lower elevation slopes where you might be able to trigger a wet avalanche.  Strong southwest winds, which will intensify overnight, should ventilate most of the solar oven-like slopes I'm concerned about, and thickening clouds should help keep a lid on the solar heating.  But greenhousing is a possibility, especially in sheltered areas. 

Most of the wind-drifts formed by Tuesday's strong wind stayed locked in place, and I've only seen one natural wind-drift avalanche in fairly extensive travels in the backcountry.  Some thick and very solid drifts are resting on weak sugary or faceted snow, but you'd have to really thump one on a steep slope to get it moving.  Unfortunately, on Friday sustained pre-storm winds will likely be strong enough to form new stiff drifts with existing soft snow above about 8000'.  The re-crystallized snow and frost or surface hoar now on the snow surface in many areas might make for a nice weak layer if overloaded by a wind-slab.  While building, some of these drifts might be sensitive to your weight.  You'll easily be able to identify problem areas, and you should avoid stiff feeling, chalky looking, and hollow sounding drifts on slopes steeper than about 35 degrees.  Drifting near ridgetops and around terrain features like gullies and sub-ridges on Friday will be limited to upper elevations, where there's still some powdery snow on the surface.  With strong southwesterly winds, we'll need to watch for drifts mainly on lee, north and east facing slopes, but some could cross-load onto other slopes as well.

Bottom Line:

There's a MODERATE danger and you might trigger avalanches on some upper elevation wind-drifted slopes steeper than about 35 degrees.  This danger will increase and become more widespread throughout the day with sustained southwest winds and possible snowfall.  There's a LOW danger on sheltered slopes facing the northern half of the compass, but solar warming in the heat of the day may cause a MODERATE danger of wet avalanches on steep mid and low elevation slopes with saturated snow.

Mountain Weather:

Southwest winds will intensify overnight and be strong in the mountains all day tomorrow.  It will be mostly cloudy with high temperatures at 9000' around freezing.  Thunderstorms may rock to region in the evening with frontal passage.  After dropping several inches of snow on our mountains the storm will rapidly move off to the east, and cold air will move in overhead.  Clouds and some snow showers will continue for much of Saturday.  Temperatures will rebound with fair weather on Sunday, and a potentially strong storm will move in around Tuesday.

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 Friday night.  I will update it again Saturday morning by about 7:00.

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.