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 23, 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 23rd at 9:30 pm.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Avalanchetools.com.

Current Conditions:

After a couple warm days, spring powder stashes are now limited to upper elevation north facing slopes. Today, the surface snow at lower and mid elevations got pretty sloppy, and in some places I was sinking into knee-deep mush even with my skies on.  With only a light refreeze probable overnight, any crusts that form will probably disappear quickly in the heat of the powerful spring sun.  If you're looking for spring corn snow conditions, you're gonna have to wait for a little while.  Remember extra sunscreen, a ball cap, and skin wax if you head out.  It will be easy to get your sled stuck in wet snow at lower and mid-elevations, but upper elevation snow should offer decent riding conditions.

Snow and Avalanche Conditions:

 I don't think it will get cold enough overnight to significantly refreeze the now sodden snow, especially at lower and mid-elevations.  Wet avalanches will be our primary concern on Friday, and these will be most likely in the heat of midday and into the afternoon.  Rapid warming also may be increasing the possibility of slab avalanches. The warming leads to accelerated creep and glide rates.  Different layers move downhill at different speeds, and weak layers can be stressed to the breaking point.  Also existing hard slabs are softened by heating, and they become more susceptible to triggering. Which is to say, they become more sensitive to human weight or the weight of possible overriding wet avalanches.

I had a chance to get a better look at the recent extensive natural avalanche activity on the eastern slopes of the Wellsville Range.  I triggered a few large audible collapses as I crossed through shallow areas with saturated snow, and in some areas I could easily plant my ski-pole through very soft snow all the way to the ground.  I could see evidence of lots of pretty big soft-slab avalanches, which ran under the cover of clouds sometime between Sunday and Tuesday.  Also, from across Cache Valley this morning, I could see one huge hard slab avalanche north of Wellsville Cone in Shumway Canyon.  It's a bit hard to estimate the size from afar, but I think 2-meter-deep crown is several hundred feet wide. I'm heading up in the morning to investigate further.  In the space of a couple hours, while I was delving into the wilderness near Maple Bench, a couple significant wet avalanches spontaneously ran around 1500 vertical feet down steep southeast facing slopes, creating large debris piles in the long runout gullies.

Bottom Line:

There's generally a MODERATE danger and you could trigger avalanches on sun-warmed or saturated slopes steeper than about 35 degrees in the backcountry.  As temperatures climb through the day, the danger of wet or heat triggered avalanches could rise to CONSIDERABLE in some areas.  This means you could probably trigger significant avalanches on many slopes, and some natural avalanches producing large deposition piles could spontaneously occur.

Mountain Weather:

Overnight temperatures may drop into the upper 20s at the highest elevations, but they'll stay near or above freezing in many mountain areas. Tomorrow will be sweltering, with 40-degree high temperatures forecast for 9500'.  Southerly winds will increase and it'll be warm again on Saturday, (leading to more melt,) before the next spring storm moves in Saturday night.

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 on 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.