Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Wednesday - February 8, 2017 - 6:32am
bottom line

The danger is CONSIDERABLE at all elevations in the backcountry. Drifting from strong and sustained southwest wind, copious heavy snow, warm temperatures, and rain have created dangerous avalanche conditions. Triggered wind slab avalanches are likely in drifted upper and mid-elevation terrain. Storm, persistent, and wet slab avalanches are possible across the zone, and dangerous wet avalanche conditions exist on low elevation slopes with saturated snow. Carefully evaluate the snow, be conservative in decision making and route finding, avoid drifted terrain and stay out from under low elevation slopes with saturated snow.
special announcement

Thursday 2/9- This week the Utah Adventure Journal Speaker Series hosts professional ski-mountaineer Andrew McLean. Andrew has a PhD in mountain mistakes and will be sharing lessons learned from personal ski mountaineering experiences with avalanches, crevasses, long falls, getting lost, partner malfunctions and many other mountain mishaps. Andrew is the author of The Chuting Gallery and a veteran of over 25 skiing expeditions. For all event details click here.
current conditions

The 8400' Tony Grove Snotel reports 27 F and 16" of heavy new snow with 3.4" SWE (Snow Water Equivalent) in the last 48 hours. There's 109" of total snow containing 166% of average SWE. It's 20 F at the CSI Logan Peak weather station at 9700', and the wind is from the west at 14 mph, gusting to 44 mph early this morning. Southwest winds were quite strong yesterday, with hourly average wind speeds 35 to 45 mph for several hours and a gust of 87 mph around 1:00 in the afternoon. Dangerous avalanche conditions exist on many slopes in the backcountry.
recent activity

Heavy rain and warm temperatures tipped the scales at low elevations yesterday. At least three natural loose wet avalanches hit and crossed Hwy 89 in the Dugway section of Logan Canyon starting about 12:30.

Other large natural wet avalanches occurred yesterday and over the weekend at low elevations in Logan Canyon and various other canyons across the Logan Zone.

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

Drifting from strong southwest winds created fresh wind slabs and built out cornices in exposed terrain.

  • Wind slabs made up of stiffer drifted snow often look rounded and chalky and may produce hollow, drum-like sounds.
  • Avoid drifted snow on the lee side of ridges and in and around terrain features like gullies, scoops, sub-ridges, and cliff-bands.
  • Cornices could break further back than expected and may trigger avalanches on drifted slopes below.
  • Storm slab avalanches entraining the heavy new snow are also possible in more sheltered terrain.
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

Dangerous wet avalanche conditions exist on slopes with saturated snow. Natural sluffs entraining loose wet snow are likely, and triggered wet slab avalanches are possible on slopes with buried persistent weak layers. A thin veneer of crust likely formed on the wet snow surface overnight, and this will help hold the saturated snow together until it softens in today's warmth. If you start sinking past your ankles into the wet snow, it's probably time to leave the area. Roller balls, pinwheels and wet sluffs are indicators of growing wet avalanche potential. Avoid and stay out from under steep slopes with melt-softened wet snow.
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

Triggered persistent slab avalanches around 2 feet deep are possible on mid-elevation slopes with buried persistent weak layers. The new load from yesterday's heavy snow may activate the buried weak layers and dangerous conditions could exist in some areas.

  • Buried surface hoar exists mainly in sheltered mid and lower elevation terrain, but is found on east, north, and west facing slopes.
  • A weak layer of small facets on top of a sun-crust still plagues some sunny mid elevation slopes.
  • You will have to dig down into the snow a couple feet to find the buried persistent weak layers.
weather

High pressure will build across the region through midweek. A strong pacific trough is expected to impact the region Friday into Saturday. Snow showers are possible and it'll be mostly cloudy in the mountains today. High temperatures at 8500' will be near 34 F, with 25 to 30 mph west winds gusting into the 40s. Snow is likely tonight, with 2 to 4 inches possible and breezy conditions, west wind of 25 mph. The temperature will rise to around 41 F around 0300. There is a chance of snow Thursday, and it'll be warm, around 42 F at 9000'.
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.