Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Friday - February 17, 2017 - 6:45am
bottom line

The danger is LOW and snow is mostly stable in the backcountry. Even so, triggered wind slab avalanches are possible on drifted upper elevation slopes. Daytime warming will cause a rising danger of shallow wet avalanches entraining loose saturated surface snow. Use normal caution, and avoid drifted slopes at upper elevations and steep slopes with saturated surface snow above trees, cliffs, or other terrain traps.
current conditions

The 8400' Tony Grove Snotel reports 26 F and 98" of total snow containing 160% of average SWE (Snow Water Equivalent) . It's 23 F at the CSI Logan Peak weather station at 9700', and the wind is from the southwest at 16 mph. There's a few inches of settled powder on shady upper elevation slopes, but the week-old snow has seen too much wind, sun, and warmth elsewhere, creating variable conditions. Under the soft surface is a thick and hard crust formed by warmth and copious rain last week. Small wind slab avalanches and shallow wet sluffs are possible involving surface layers, but the bomber crust is holding the deeper snowpack together.

recent activity
  • Numerous shallow sled and board triggered wind slabs were reported from drifted upper elevation terrain in the Bear River Range last weekend and early this week. The expected and easily triggered shallow soft slab avalanches occurred on very steep slopes, and were about 8" deep. Several triggered wet and dry sluffs were also reported.
  • Warmth trapped by yesterday's thin clouds affected the snow on north facing mid-elevation slopes yesterday and my party triggered a few small wet sluffs in South Wood Camp in the afternoon.
  • A party observed a huge cornice that had recently cracked deeply and collapsed on the ridge above DB Bowl in Logan Dry Canyon. There were sled tracks in the area of the fracture, but it's unknown if the collapse was triggered or if it occurred after the fact.

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 possible at upper elevations. Strong southwest winds yesterday drifted surface snow into terrain features and lee slope starting zones, creating shallow but stiff wind slabs. Drifts formed on weak faceted snow above last week's thick crust and could be pretty sensitive today. Wind slab avalanches will probably be fairly small but they could run fast and far on the rain-crust.
  • Cornices are suspect due to the recent warmth and wind. Avoid travel on or below large overhanging cornices, especially in the 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
  • Loose snow above the thick crust quickly became faceted this week on shady slopes, and triggered long running loose dry sluffs are possible at upper elevations. As this snow is warmed by daytime heating, it'll be prone to sluffing.
  • Solar warming and/or greenhousing will cause an increasing danger of shallow loose wet avalanches on steep slopes. Triggered wet sluffs will entrain a few inches of sloppy, saturated snow and run on last week's thick crust.


  • Triggered wet sluffs above Tony Grove Lake (Flygare 2-13-17)
weather

The upper level trough off the California coast will send moisture along with a series of weather disturbances across Utah through the weekend. High pressure aloft will return early next week, followed by another round of active weather midweek. Snow is possible this afternoon, but less than an inch is expected. We'll see increasing clouds, and a high temperature at 8500' of 38 F. Light winds will become 5 to 7 mph from the south-southeast in the afternoon. 2 to 4 inches of snow is expected tonight, with a low temperature of 29 F and 7 to 17 mph south-southwest wind. Snow is likely tomorrow morning, but looks like we'll be lucky to see more than a half inch. It'll be cloudy with a high temperature of 36 F and breezy, with 21 to 26 mph south wind, gusting to 40 mph. A couple inches of snow is possible Saturday night, with southwest wind 8 to 15 mph, and a low temperature of 29 F.
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.

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.

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.