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Logan area Avalanche Advisory

Wednesday January 9, 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 Wednesday January 9th, and itís about 7:30 in the morning.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Backcountry Access.

†††††††††††† Current Conditions:

A Winter Storm Warning remains in effect until this evening as even more powder stacks up in the mountains.Ben Lomond Peak Snotel is the big producer this morning with 2.1 inches of water equivelent since yesterday afternoon.The Tony Grove Snotel picked up a solid inch of water in several inches of snow, and Iím now reading 70 inches on the total snow stake.Overnight southwest winds at CSI weather on Logan Peak averaged in the upper twenties for several hours with higher gusts.Iím noting a west, northwest windshift now, and speeds are holding in the teens.Itís 15 degrees at 9400í and 30 degrees down in Mendon.Luckily, the copious deep powder snow will keep us all satisfied on gental slopes and at lower elevations.The deep, soft snow will keep most of us out of danger with difficult trail breaking and getting the sled stuck conditions.

††††††††††† Avalanche Conditions:

No avalanches observed or reported from the backcountry around Logan since Saturday 1/5 naturals. The moist snow from that storm set up solidly, like plaster capping underlying weaknesses, and now weíve got a couple feet of powder stacked up on it.There was limited time for surface weaknesses to develop before more snow accumulated.This means avalanches today will consist of new snow or wind slab avalanches running on freshly deposited weak layers, or huge catastrophic avalanches breaking into weak sugary snow near the ground.

The additional weight from todayís storm might be just enough to put some slopes over the edge.Iíd not be surprised to see a few full-depth natural avalanches on slopes cursed by faceted snow near the ground and overloaded by todayís new water weight.The good news is that the Deep Slab instability caused by faceted or sugary snow near the ground is now so deeply buried in many places that your weight alone is probably not enough to activate it.The bad news is you might not get any tell-tail signs of danger until you actually trigger the slab from a shallow spot. Potential large hard slab avalanches could be several feet deep, very broad and deadly.†††Possible trigger spots include rocky or generally shallow areas, like cliffy lower elevation areas or upper elevation slopes scoured by previous northwest winds. Possible triggers include overrunning smaller new snow avalanches, additional loading from heavy snow and especially wind drifting, cornice fall, and Humans.

Increasing winds today may cause a rising danger.Watch for fresh or forming wind slabs, and avoid them on steep slopes at all elevations.Be wary of the dangerous combination of depth hoar and recent drifting at mid and lower elevations.

†††††††††††††† Bottom Line:

Thereís a CONSIDERABLE danger and you could trigger dangerous avalanches on many steep slopes in the backcountry, mainly in exposed upper elevation terrain. Increasing winds today could cause the danger to rise or become more widespread. There may already be a HIGH danger in some areas like at upper elevations in the Wellsville Range, with some very large full-depth natural avalanches possible.

†††††††††††††† Mountain Weather:

†††††††† Expect more snow this morning with an increase in winds possible around midday.Should see a short-lived break this evening, but clouds ahead of the ††††††next storm will move in quickly.Several more inches of snow are possible as storminess continues tomorrow.A high pressure tries to move in this weekend, but weíll likely see northern brush-bys next week.

General Information:

I will give a free avalanche awareness talk for snowmobilers at Renegade Sports on Thursday January 10th at 7:00.

Check out photos of 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'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.