Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Thursday - December 19, 2013 - 6:51am
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Heavy snowfall is creating dangerous avalanche conditions and a Level 3 or CONSIDERABLE danger in some areas. The welcome new snow is piling up on widespread preexisting very weak faceted snow. Natural avalanches are possible and triggered avalanches likely in areas with significant overnight accumulations. You could trigger avalanches remotely, from a distance or below. Avoid and stay out from under steep slopes with significant accumulations of fresh snow. Very shallow and rocky early season snow conditions exist across the Logan Zone. Careful snowpack evaluation, cautious route-finding, and conservative decision making will be essential in the backcountry today.




special avalanche bulletin

Heavy snowfall on very weak preexisting snow is creating dangerous avalanche conditions in the backcountry today.  Natural avalanches are possible and dangerous human triggered avalanches are likely in areas with significant overnight accumulations.

current conditions

Overnight accumulations varied significantly from place to place, with Ben Lomond Peak Snotel above the northern Ogden Valley reporting 11 inches with close to an inch-and-a-half of water, and Beaver Mountain picked up 5" of new snow. The Tony Grove Snotel at 8400' reports 6" of new snow containing 1/2 inch of water equivalent. It's 28 degrees this morning, and there is 28 inches of total snow containing 55% of average water content for the date. The 9700' Logan Peak weather station reports 23 degrees and northwest winds averaging a bit less than 10 mph this morning. The fresh snow is piling up on a variable old snow surface; wind-jacked and sun-crusted in exposed terrain, rotten, weak, and unsupportable in more sheltered and shady areas. Widespread, very weak preexisting faceted snow plagues most slopes in the region, and is especially bad on upper and mid elevation slopes facing the northern half of the compass. The Tony Grove Road is not maintained for wheeled travel in the winter, and the road is currently very snowy, icy, and treacherous in places. A sled or a 4-wheel-drive vehicle and chains are recommended.

Faceted snow is widespread, very weak and getting weaker. This photo was taken on 12-17-2013 in the White's Bedground Area off Red Pine Ridge.

A video observation from Red Pine Ridge 12-17-2013 is HERE

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

Slopes with significant fresh accumulations could produce dangerous avalanches today. Weak surface snow and frost crystals or surface hoar was observed on many slopes before last night's snowfall, and the heavy new snow will probably not bond well. Natural storm snow avalanches are possible and triggered avalanches likely today on slopes with close to a foot or more of heavy new snow.

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

Heavy new snow is rapidly piling up on top of preexisting very weak sugary or faceted snow, which is widespread in the region. Natural avalanches failing in old weak faceted snow or in the basal layers of the existing snow pack are possible and dangerous human triggered avalanches likely in areas that picked up significant accumulations overnight. You could trigger persistent slab avalanches remotely or from a distance today, and this could be an especially bad scene if you trigger one from below. Collapsing and/or shooting cracks are obvious red flags requiring you to reevaluate your route. Avoid and stay out from under steep slopes, slopes connected to steep slopes and obvious or historic avalanche paths today.

weather

Snow is falling in the region this morning and should continue for a while. 2 to 4 inches of additional accumulation is expected in the mountains today, with 8500' high temperatures around 31 degrees. Moderate west winds today will become northerly this afternoon and be out of the northeast by evening. Another storm, perhaps a bit stronger, will move into the region tomorrow night bringing a good chance for more accumulating snow through Saturday...

Check out our one stop weather page........HERE

general announcements

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Remember your information can save lives. If you see anything we should know about, please participate in the creation of our own community avalanche advisory by submitting snow and avalanche conditions. You can also call us at 801-524-5304 or 800-662-4140, email by clicking HERE, or include #utavy in your tweet or Instagram.

I'll issue advisories on Monday, Wednesday, Friday, and Saturday mornings. 

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.