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.

                        The Utah Avalanche Center Home page is: http://www.avalanche.org/~uac/

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Logan area Avalanche advisory

Sunday February 11, 2007:

  Hello and good morning, this is Toby Weed of the Forest Service Utah Avalanche Center with your Logan Area backcountry avalanche and mountain weather advisory.  It’s Sunday February 11th, and it’s 7:30 am.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Backcountry Access.

AN AVALANCHE WARNING HAS BEEN ISSUED FOR THE MOUNTAINS OF NORTHERN UTAH FOR TODAY THROUGH MONDAY.   HEAVY SNOWFALL AND MODERATE TO STRONG WINDS WILL LEAD TO UNSTABLE AND DANGEROUS AVALANCHE CONDITIONS.   BACKCOUNTRY TRAVELERS SHOULD AVOID BEING ON OR UNDERNEATH STEEP SLOPES.

Bottom Line:

 There's a CONSIDERABLE avalanche danger in the backcountry, and triggered slab avalanches are probable on slopes steeper than around 35 degrees with substantial recent deposits of heavy or wind-drifted snow.  With less overnight snowfall in the Central Bear River Range, this morning's danger may be limited to upper elevations and slopes facing the northeastern half of the compass.  However,  heavy snowfall and constant west and southwest winds later today will likely cause the danger to increase and become more widespread.  In areas that received more snow overnight, like the Wellsville Range, the Southern Bear River Range, and the mountains above the Ogden Valley, the overall danger is already HIGH, and dangerous avalanches stepping down into persistent buried weak layers are likely.  Backcountry travel is not recommended in these areas.

Current Conditions:

  The bulk of the snowfall occurred right on the Wasatch Front Ranges and to our south.  The Tony Grove Snotel reports 24 hour total of 3/10ths of an inch of water in around 3 inches of snow, while Ben Lomond Peak shows 1.5 inches of water in a solid foot of heavy snow.  Overnight, consistent southwesterly winds increased for a while, with 40 mph wind speeds common on the highest peaks.  After a let-down in precipitation and wind this morning, the Pacific water-hose will turn on again and heavy snowfall is likely with the passage of a cold front this afternoon.  The rain/snow-line is fairly high, >7000', and mountain temperatures are hovering around freezing, but both should drop drastically with frontal passage.

Avalanche Conditions:

 Heavy wet snowfall and constant southwesterly winds overnight built a dangerous slab on very weak snow in many areas.  This morning I'm most concerned about the Wellsville Range, the mountains above Mantua and the Ogden Valley, and the Logan Peak Areas, where we appear to have received a substantial load of heavy new snow overnight. On steep slopes in areas that received the most accumulation, dangerous slab avalanches consisting of heavy storm snow are likely to step down into old buried weak layers.  You should avoid and stay out from under slopes steeper than about 35 degrees in the backcountry.

 In northern and eastern areas, significantly less snow fell, but the avalanche danger may rise quickly as new snow piles up this afternoon.  Today in the Central Bear River Range you are likely to trigger fresh wind slab avalanches (video clip) on steep drifted slopes in exposed terrain.  Dangerous triggered avalanches involving existing persistent weaknesses will become more probable and the danger more widespread this afternoon as more snow accumulates.  Avalanche training and experience are essential for safe backcountry travel.

Mountain Weather:

The National Weather Service Has issued a snow advisory for the mountains of Northern Utah through 9:00 tonight.  After a pause in the action this morning, snowfall will continue in earnest this afternoon.  Frontal passage is expected in the evening hours, with declining temperatures and the snow-line dropping toward the benches.  Periods of mountain snowfall should continue into Monday.  A mid-week storm will mainly affect Central and Southern Utah...

 General Information:

Check out the recently released Media Page, which shows the current and forecast danger for our coverage areas across the state.

 This advisory will expire on Monday morning. I will update it again on Tuesday 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.

Thursd