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

Special Update

January 4, 2007

Hello and good morning, this is Toby Weed of the Forest Service Utah Avalanche Center with a special update of the backcountry avalanche and mountain weather advisory.  It's Thursday January 4th, and its 7:00 am.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from The Trailhead.

Bottom Line:

There's a CONSIDERABLE avalanche danger on steep wind drifted slopes at upper elevations.  Triggered wind slab avalanches are possible on many exposed slopes, with the danger most pronounced above about 8000' on slopes steeper than around 35 degrees facing north, east, and south.  Some natural wind slab avalanches are also possible.  Avalanche training and experience are essential for safe travel in exposed upper elevation terrain today.  With significant snowfall and wind, the danger on steep slopes in more sheltered terrain and at mid-elevations will rise to MODERATE, and triggered soft slab or storm snow avalanches will be possible in some areas.

Mountain Weather:

The National Weather Service has continued a Winter Storm Warning for the Northern Utah Mountains through 8 pm tonight.  Periods of heavy snowfall today could be accompanied by strong northerly winds.  This morning's light snowfall will turn heavy as a cold front moves southward over the mountains during the day.  A northerly flow tends to shut us down, but 8 inches to a foot of additional accumulation is possible at upper elevations before things peter-out this evening.  The quick-hitting storm will be well to our south and east on Friday, but it looks like we could see a bit more snow on around Saturday night.

Current Conditions:

At 6:00 this morning, the Tony Grove Snotel site reports 8/10s of an inch of water accumulation overnight in several inches of rather heavy snow.  Of perhaps more concern, the wind speed sensor at the Campbell  Scientific weather station on the summit of Logan Peak recorded a sustained period with high propeller speeds overnight, as it was blasted by strong westerly winds.  Winds from the west pushed out hourly averages in the upper 30 mph range, with a 75 mph gust recorded a little after midnight.  The wind is already out of the north this morning and it appears to be moderating.  Temperatures are dropping as well, and it's down to 17 degrees at 9500'.

Avalanche Conditions:

I'm mostly concerned by last night's strong winds, which undoubtedly produced significant drifts and wind slabs with the freshly fallen snow.  The avalanche danger on steep wind drifted slopes increased drastically overnight, and you could probably trigger avalanches on numerous upper elevation slopes in the backcountry today.  The drifts or slabs formed in exposed terrain on lee east facing slopes and cross-loaded into north and south facing slopes.  In many cases wind slabs may have built up on top of existing weak surface snow, which has turned sugary or faceted because of temperature gradient metamorphism during the late high pressure system.

The situation will be made more complicated by significant snowfall and potentially strong northerly winds today.  For one thing, last night's stiff drifts will be obscured and hidden by the fresh powder. You might not have any idea that a significant new trap that might normally be obvious, exists lurking underneath the surface.  During periods of heavy snowfall and strong winds, new drifts and soft slabs will form on a whole new set of slopes, and developing instabilities will continue to be overloaded.  Soft slabs consisting of new storm snow will likely become possible on steep slopes in more sheltered terrain by this evening.

General Information:

The Friends of the Utah Avalanche Center-Logan will present the 3rd annual fundraiser on Friday, January 19th at the Bullen Center in downtown Logan.

For cool pictures of some of 2006's avalanche activity, including last week's avalanches, visit our Images Page.

These advisories are updated on Tuesday and Thursday evenings and weekend mornings by about 7:00.   I will issue an updated advisory on Thursday evening.  Logan Area advisories are accessible through the new statewide toll-free avalanche information line at, 1-888-999-4019.

Please send backcountry observations to [email protected] or leave us a message at 755-3638, especially if you see or trigger an avalanche in the backcountry.  I'm a little starved for information from you these days.  Your observations are necessary, and the information you provide may save lives. 

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.