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 8, 2007:

Hello, this is Toby Weed of the Forest Service Utah Avalanche Center with your Logan Area backcountry avalanche and mountain weather advisory.  Itís Thursday March 8th, and itís 9:30 in the evening.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Backcountry.com.

Current Conditions:

True to early March form early this morning; a quick-hitting storm hit the refresh button on the backcountry powder conditions and dumped a nice new blanket on mountain slopes across the region.About 9 inches with 9/10ths of an inch of water fell at the Tony Grove Snotel, with similar amounts in favored locations across Northern Utah. ††A fairly strong southwesterly wind built stiff drifts in exposed, upper elevation terrain throughout the day today.I found ride-anywhere conditions, with mostly supportable snow underneath and smooth and enjoyable, if somewhat heavy, powder all slopes above about 7500.í I felt inclined to spend the afternoon today in the sun on stable slopes with nice snow that are often ruined by the time I get there.Itíll warm up drastically again in the afternoon, with clouds trapping the heat from periods of sunshine and turning the mountain air hot and muggy, like a giant greenhouse.

Avalanche Conditions:

There havenít been any recent avalanches reported in the backcountry for nearly a week.Weíre still finding more evidence of last Fridayís extensive natural cycle, which appears to have been much more widespread south of Logan Canyon.Warmth is likely to cause avalanche problems this weekend.

The deeply buried persistent weak layers responsible for the recent local huge hard slabs are notoriously slow to heal. With time you are less likely to trigger one of these killer avalanches but if you hit a shallow spot on a slab just right, you will awake a monster. The warm temperatures increase the creep rate of the slab over the buried weak layers, and a few significant natural avalanches may result.Another problem with the warmth is slab softening, which may make thick slabs more susceptible to being triggered by your weight.†† Wind slab or wet avalanches overrunning slopes with deeply buried weak layers could trigger much larger and deadly hard slab avalanches.

Strong westerly winds built drifts and sensitive wind slabs along ridge-lines and in exposed terrain.Most of these should be obvious on Friday and as usual, you should avoid all chalky looking and hollow sounding drifts on steep slopes.Fresh wind slabs in the 1 to 1.5 Ď deep range are likely, but the weight of a smaller avalanche overrunning some slopes could be enough to trigger a deeper and more dangerous hard slab avalanche.

Bottom Line:

There is a MODERATE danger and triggered avalanches are possible on steep slopes in the backcountry.Wind slab avalanches are possible on some drifted slopes, most likely facing north through east and above around 8500í in elevation.Loose wet avalanches are possible on slopes heated by solar warming or greenhousing.Some avalanches could step down into deeply buried persistent weak layers and could be large, destructive and deadly.

Mountain Weather:

Friday will be mostly cloudy and mild, with a light northwesterly breeze and mountain high temperatures around 40 degrees.A few snowflakes are likely late Friday night, but the weekend looks fair and warm.A high pressure system will start to build over the region and looks like it will control the weather for the early part of next week.

General Information:

For more information on last week's accidents from the Utah Avalanche Center, go to accidents

Check out photos of last week's avalanches in the Logan Area on our images page.

Go to the Avalanche Encyclopedia if you have any questions about terms I use in the advisory.  I also recommend the recently-released Media Page, which shows the forecast danger for our coverage areas across the state.

Please e-mail me at [email protected] or leave me a message at 755-3638 if you see or trigger avalanches in the backcountry.  The information you provide may save lives...

This advisory will expire on Friday night.  I will update it again on Saturday morning.

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.