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Logan area Avalanche Advisory

 

7:30, Monday March 31, 2008

Hello and good morning, this is Toby Weed of the Utah Avalanche Center with your Logan Area backcountry avalanche and mountain weather advisory.  Itís Monday March 31st, at 7:30 in the morning.Todayís advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Backcountry.com.

Current Conditions:

Itíll feel a lot like winter today in the mountains with diminishing snow showers, mostly cloudy skies, cold temperatures, and a bighting north wind.You should be able to find a bit of the ďgreatest snow on earthĒ in the backcountry, with good to excellent powder conditions likely on many upper and mid elevation slopes today.Youíll probably find dust-on-crust or even shallow powder on somewhat breakable crusts at lower elevations and on slopes affected by spring heating on Saturday.Iím reading 14 inches of fluffy new snow containing 6/10ths of an inch of water at the Franklin Basin Snotel just north of the Idaho State Line and around 9 inches with Ĺ inch of water at the Tony Grove Snotel.Thereís 107 inches of total snow on the ground at 8400í, containing 106% of average water for the date.Overnight winds on Logan Peak averaged less than 20 mph and are now from the north, reading around 15 mph.Itís a bitter cold and even zer0í at the Campbell Scientific weather station at 9400í and 19 degrees down here in LoganÖ.

Avalanche Conditions:

Over the weekend, weíve received numerous reports of sensitive triggered shallow soft slabs from the Central Wasatch backcountry.These new snow avalanches have been releasing on a less dense layer of somewhat inverted and drifted new snow (Wasatch Advisory). It was a fairly quiet weekend locally, with many natural dry sluffs in steep terrain on Saturday morning (photos), and cornice fall and shallow soft wind slabs with the last significant snowfall on Thursday (more photos). ††

With lots of fresh driftable snow about and increasing westerly winds forecast, freshly formed or forming wind slabs are my primary concern. Triggered wind slab avalanches are most likely on steep upper elevation slopes with significant deposits of new or recently drifted snow, and some naturals are possible, especially if wind speeds increase. Fresh drifts should be fairly obvious, and you should avoid them on steep slopes. Significant loose sluffs involving the fresh powder are likely in steep terrain and some could overwhelm or knock you over especially in gullies. Many avalanche slide paths in the area are well filled-in and smooth, so even relatively small avalanches might run far or fast.As is typical in the springtime, wet avalanches may become possible on steep slopes as warmth from even short periods of sunshine turns the fresh surface snow into slush.†† You might find even smallish wet avalanches entraining lots of mass and traveling far.†† Relatively cool temperatures and lingering cloud cover should help to keep the snow dry, but this time of year, any solar warming can be very intense and when the fresh snow becomes saturated is prone to avalanching.

The huge cornices in the region now present an obvious danger, especially when itís windy or warm. Large cornices may be sensitive to your weight today and may break further back than you expect.†† It is always a good idea in the spring to stay out from under these monsters.

Bottom Line:

Overall thereís a MODERATE avalanche danger in the backcountry, and you could trigger wind slab or storm snow avalanches on some slopes steeper than about 35 degrees. ††The greatest risk and pockets with a CONSIDERABLE danger exist on steep, drifted or corniced slopes in exposed terrain at upper elevations.This means triggered avalanches are probable and naturals are possible in some areas. Wet avalanches may become possible on some slopes if the sun comes out and the fresh surface snow is warmed and becomes saturated.

Mountain Weather: The cold front is on its way south and east this morning, and we should see diminishing snow showers and cloud cover today.Itíll be unseasonable cold and it could be rather breezy, with west winds forecast to increase a bit in the middle of the day.The next storm will affect the region beginning with light snow tomorrow afternoon and lasting through around Thursday.

General Announcements:

Check out the images page for photos of some of this seasonís 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.

This advisory will expire in 24 hours from the posting time.

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.