Avalanche Advisory
Advisory: Salt Lake Area Mountains Issued by Evelyn Lees for Wednesday - February 7, 2018 - 6:52am
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The Avalanche Danger is MODERATE on steep, mid and upper elevation slopes facing west through north through east, for triggering a 2-foot deep slab avalanche failing on weak faceted snow grains. Loose sluffs and sensitive wind drifts can also be triggered on steep slopes, with wet loose sluffs becoming an issue on sunny slopes with daytime heating.




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current conditions

Under mostly clear skies, it actually feels like winter this morning – temperatures are in the teens. Combined with brisk winds, the wind chill is down around zero this morning. The west to northwesterly wind speeds are variable, occasionally reaching 20 mph averages, with gusts in the 30s, at 10,000’. High peaks have had 30 mph averages, with gusts in the 40s, the past 12 hours.

Snow the last 48 hours added up to a great little refresher for the Salt Lake and Park City mountains – 4 to 7” new snow, with a denser graupel base. It keeps you off the crusts on low angle slopes, and adds to the softer snow on the shady slopes.

recent activity

Decent size dry loose sluffs were the only activity mentioned in the few backcountry reports.

Sluffs in Cardiff Fork. Mark White photo

Avalanche Problem 1
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 12 hours
description

While it’s been over a week since a slide was triggered on one of the buried faceted layers, the additional weight of ½ to ¾ of an inch of water in the recent snow could be just enough to make these layers more sensitive again.

By avoiding steep northwest through easterly facing slopes, especially where wind drifted, you can avoid triggering one of these slides. Shallower snowpack areas are particularly suspect – such as rocky rollovers and the Park City and Millcreek ridgelines and drainages.

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

Wind Slabs:

The westerly winds now have some snow to work with, so expect to find soft wind drifts along the ridgelines, most widespread on slopes with an easterly aspect. Avoid steep slopes with wind drifts, which often look smooth and rounded, or are on slopes below small, new cornices.

Loose Dry Sluffs

Dry loose sluffs can be triggered on steep slopes of all aspects, but will be largest on shady, upper elevation slopes. They are just hefty enough to knock you off your feet and take you for a ride.

Loose Wet Sluffs

Direct sun and warming temperatures will quickly heat the snow on the sunny slopes today. Wet loose sluffs will be easily triggered, and run further than expected on the hard ice crusts beneath. A few natural wet sluffs are possible.

weather

A mild northwest flow will continue over the area through Friday. Mostly clear skies this morning, with increasing clouds this afternoon. Temperatures will warm to near 40 at 9,000’. The westerly winds will average 5 to 15 mph at the mid elevations, with the high peaks reaching averages of 25 to 35 mph at times, with gusts in the 40s. The next chance for a few inches of snow is Saturday.

general announcements

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This information does not apply to developed ski areas or highways where avalanche control is normally done. This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.