Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Wednesday - January 20, 2016 - 6:26am
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HIGH (level 4): Very dangerous avalanche conditions exist in the backcountry and people should avoid travel in avalanche terrain. Triggered and natural avalanches are likely on recently drifted slopes steeper than about 30 degrees. Continue to avoid travel on or beneath steep drifted slopes and obvious or historic avalanche paths. Avalanches could be triggered remotely, from a distance or even below!




current conditions

Dangerous avalanche conditions still exist today on drifted slopes in the backcountry, and you should stay off of and out from under drifted slopes steeper than about 30 degrees. The temperature is 23 degrees and I'm reading a couple inches of new snow from overnight, containing .7" of water at the 8400' Tony Grove Snotel. There's now 66 inches of total snow, containing 100% of average water content for the date. The 9700' CSI Logan Peak weather station reports 16 degrees this morning and significantly increased southwest winds overnight, with current west wind speeds averaging around 25 mph, and gusting close to 60 mph.

A large sled triggered avalanche from yesterday in Christmas Tree Bowl just north of Naomi Peak in Bullen Basin. The avalanche was triggered from very low on the slope. (J. Lundahl 1-19-2016)
recent activity

  • Several large sled triggered avalanches were reported from yesterday in the Tony Grove Area. These were triggered from low on the slopes on east and south facing terrain.
  • At least one unintentional triggered avalanche occurred Sunday in backcountry terrain accessed from Beaver Mt.
  • Observers report seeing some natural avalanches on the western slope of the Bear River Range from Cache Valley, and I could see a few from the Top of Beaver Mt. yesterday. But, we saw less natural avalanches than I thought we would.
  • Observers in the Ogden and Salt Lake Area mountains reported triggered avalanche activity from the backcountry Saturday, and a backcountry skier was caught, carried, partially buried, and lost both skis in an avalanche in the Wasatch Range.
  • Local observers report easily triggering numerous sensitive fresh wind slabs, some remotely, in the Tony Grove Area Friday.
  • Natural wind slab activity occurred in many areas last week at upper elevations due to drifting, and we were easily able to trigger a foot-deep hard wind slab on an upper elevation test slope Wednesday.
  • A rider triggered, was caught, carried, partially buried, and injurred on New Years Eve in a large and scary avalanche on a slope with a history of avalanche accidents in the Middle Fork of St. Charles Canyon a few miles north of the Idaho State Line. Video Report

***To view our updated list of backcountry observations and avalanche activity from around Utah, go to our observations page

Avalanche Problem 1
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

Southwest winds overnight, and drifting snow from westerly winds today will build fresh drifts in deposition areas and add weight to existing wind slabs. Many wind slabs were sensitive to human triggering yesterday, and more drifting is likely during accumulating snowfall today. Avoid recent drifts and/or stiffer wind slabs near ridge tops and in and around terrain features like gullies, sub-ridges, scoops, and rock outcroppings. Wind slabs probably formed on weak faceted or feathery snow that was previously on the snow surface, which means the slabs could be reactive to our weight, and the older drifts may stay sensitive to human triggering for several days.
Avalanche Problem 2
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

Last week, we found widespread loose and very weak snow on the surface, and now a slab layer consisting of drifted new snow has accumulated on it. Triggered persistent slab avalanches are likely in some areas today, and last week's weak surface snow is now a buried persistent weak layer that could stay reactive for several days at least. Avalanches are possible on steep slopes with significant fresh and drifted accumulations even in sheltered terrain and at lower elevations. In some areas, the faceted snow in the basal layers of the snowpack may become reactivated by the recently added weight of drifted new snow. Dangerous and destructive avalanches involving old snow and failing on sugary faceted snow or depth hoar are possible today, especially in areas with shallow snow cover and poor snow structure.

***Pay close attention to signs of unstable snow like recent avalanches, whumpfing, and shooting cracks, and be willing to reevaluate your plans. In these conditions you could trigger avalanches remotely, from a distance or worse, from below!
weather

Expect snow showers in the mountains today, and some thunder is also possible. 8500' high temperatures will be around 21 degrees and west wind in the 20 to 30 mph range, with gusts in the mid forties. 3 to 7 inches of accumulation is expected. Scattered snow showers are possible tonight, and temperatures will drop to around 16 degrees and west-northwest winds will diminish to 10 to 20 mph. It'll be mostly sunny tomorrow with a high temperature around 30 degrees and fairly light southwest wind.
general announcements

Presenting our Avalanche Awareness Class in Logan beginning the January 21, with a full field day in the backcountry on Saturday January 23.   Go HERE for more information and to sign up.

The CROWBAR backcountry ski race will be Saturday January 30. More info at http://CrowbarSkiRace.org.

Please submit snow and avalanche observations from your ventures in the backcountry HERE. You can call us at 801-524-5304 or email HERE, or include #utavy in your Instagram or Tweet us @UAClogan. To report avalanche activity in the Logan Area or to contact the local avalanche forecaster call me, Toby, at 435-757-7578. 

I'll update this advisory throughout the season on Monday, Wednesday, Friday, and Saturday mornings by about 7:30

This advisory is produced by the U.S.D.A. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist.