Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Tuesday - February 21, 2017 - 5:33am
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Dangerous conditions exist at upper and mid elevations, natural avalanches are possible and triggered wind slabs likely on drifted slopes. Storm slab avalanches involving heavy new snow are possible in sheltered terrain. Wet sluffs entraining saturated surface snow could occur on steep slopes at low and mid elevations. Evaluate snow and terrain carefully, make cautious decisions, and avoid travel on or under steep drifted slopes.
special announcement

Discount lift tickets for Beaver Mountain, Snowbasin, Powder Mountain, and the Central Wasatch resorts are donated by the resorts to benefit the Utah Avalanche Center. Details and order information here.

current conditions

It could be raining a little at 8400' this morning. The Tony Grove Snotel reports 4 inches of snow and 1.1" of SWE (Snow Water Equivalent) in the past 24 hours. There was a bit more than a foot of heavy new snow up at the lake yesterday, and the station reports 2.3" SWE in the last 48 hrs. It's 35 F and there's 111" of total snow containing 165% of average SWE. It's 28 F at the CSI Logan Peak weather station at 9700', and 30 mph south-southwest wind is howling on the mountain top, gusting to 64 mph.

recent activity
  • Yesterday, I intentionally triggered a 14" deep and 20' wide storm slab on a very steep test slope at 8300' just above the Tony Grove Campground. The soft slab avalanche failed on small facets and ran on the 2/10 rain-crust.
  • Another party nearby reported triggering a couple shallow soft slabs (failing above the crust) and a long shooting crack across a steep slope.
  • ​Several people reported easily triggering wet sluffs involving saturated storm snow at mid elevations in the backcountry near Beaver Mountain Sunday.

I intentionally triggered this storm slab on a very steep test slope above the Tony Grove Campground.
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
  • Triggered wind slab avalanches are likely at upper elevations, with drifting continuing from strong southwest winds today. Drifts formed on weak faceted snow above last week's thick crust, but might not be all that sensitive to triggering after settlement. With continued drifting today, wind slabs will likely be stiffer, better connected, and less manageable than yesterday.
  • Avoid drifted snow on the lee side of ridges and in and around terrain features like gullies, scoops, sub-ridges, and cliff-bands.
  • Wind slabs made up of stiffer drifted snow often look rounded and chalky and may produce hollow, drum-like sounds.
  • Huge cornices have formed on high ridges and are suspect due to recent warmth and wind. Avoid travel on or below large overhanging cornices, especially in midday heat. Cornices can break further back than expected and might trigger avalanches on slopes below.
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

Triggered soft slab avalanches involving heavy storm snow are possible at upper and mid elevations. Storm slab avalanches may fail on a density change within the new snow or up to 2 feet deep on faceted snow above the solid and slick 2/10 rain-crust.

Avalanche Problem 3
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

Wet sluffs entraining significant piles of saturated surface snow are possible on steep low and mid elevation slopes facing any direction, most likely to occur during midday warmth. Freezing temperatures tonight will solidify the saturated snow, so we shouldn't have to worry about wet avalanches tomorrow.
weather

A mild and strong southwest flow will prevail today. A cold front tonight will usher in a period of cold unsettled weather lasting through the end of the week.

Weather Forecast: Tony Grove Lake (41.897,-111.6535), Elevation: 8800'
Today: Snow, mainly after 11am. Temperature falling to around 35 by 5pm. Windy, with a southwest wind 31 to 34 mph, with gusts as high as 48 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 3 inches possible.
Tonight: Snow. Low around 20. Breezy, with a west wind 20 to 25 mph decreasing to 13 to 18 mph after midnight. Winds could gust as high as 39 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 7 inches possible.
Wednesday: Snow likely. Cloudy, with a high near 30. West wind 9 to 13 mph. Chance of precipitation is 70%. New snow accumulation of 3 to 7 inches possible.


general announcements

Any time is a great time to practice companion rescue techniques with your partners. Companion Rescue Practice Video

Do you buy groceries at Smiths? When you register your Smith’s rewards card with their Community Rewards program, they will donate to the Utah Avalanche Center whenever you make a purchase. It's easy, only takes a minute, and doesn't cost you anything. Details here.

If you sign up for AmazonSmile and designate the Utah Avalanche Center as your favorite charity, they will donate a portion of everything you spend to the UAC. It doesn't cost you a penny and we'd really appreciate the help.

Your information can save lives. If you see anything we should know please help us out by submitting snow and avalanche observations. You can call us at 801-524-5304, email by clicking HERE, or include @utavy in your Instagram. In the Logan Area you can reach me at 435-757-7578

We will update this advisory regularly on Monday, Wednesday, Friday, and Saturday mornings by about 7:30.

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 exist.