Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Sunday - January 22, 2017 - 7:10am
bottom line

Heightened avalanche conditions exist on drifted upper and mid-elevation slopes. Strengthening south wind will cause the danger to rise and become more widespread, and dangerous avalanche conditions will develop in exposed terrain by afternoon. Heavy snow and sustained southwest winds will cause the danger in the backcountry to rise further tonight and Monday. Evaluate the snow and terrain carefully, avoid steep drifted slopes, and make conservative decisions.




special announcement

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current conditions

The Tony Grove Snotel at 8400' reports 18 F and 9 inches of snow in the last 24 hrs. There is 96 inches of total snow containing 158% of average SWE (Snow Water Equivalent). It's 12 F at the CSI Logan Peak weather station at 9700', with a 7 mph south wind. Observers report nice powder riding yesterday, with lots of very light powder and much drifting at upper elevations.

recent activity

Riders report triggering fast running sluffs in steep terrain yesterday. No significant avalanches were reported in the Logan Zone since last week's widespread, natural avalanche cycle.

Large, natural avalanches from last week in the Wellsville Range above Mendon.
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

A heightened danger of wind slab avalanches already exists in exposed upper and mid elevation terrain. Drifting from intensifying southwest wind today will cause the danger to rise and become more widespread.

  • Drifts are forming on weak surface snow consisting of surface hoar and/or small-grained sugary faceted snow, and fresh wind slabs will be sensitive to human triggering.
  • A few inches of fresh powder could be hiding recent drifts.
  • 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 wind slab avalanches on drifted 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
  • Sensitive soft slabs involving the new snow and failing on buried surface hoar are possible in sheltered terrain, especially as more snow accumulates today.
  • Loose avalanches or sluffs entraining light new snow were common in steep terrain yesterday. Get out of the way of your companions and avoid steep slopes above trees or other terrain traps.
  • Natural avalanche activity involving the new snow may occur with an increase in wind speeds or change in direction, and/or during periods of heavy snowfall.
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

Deep slab avalanches, failing on buried weak layers, are unlikely but possible.

  • Large, natural avalanches stepping into old snow were common during last week's storm at all elevations.
  • Weak layers of faceted snow exist above and below rain-crusts at mid and lower elevations.
  • The snow is weakest in rocky terrain where it's thin or shallow. Thursday, in Logan Canyon's East Banks, we found a slope plagued by depth hoar near the ground. Tests on the mid elevation west facing slope showed a propagating failure near the ground, but it was difficult to initiate.
weather

The active weather pattern will continue across the region, with a series of weather systems crossing the area through the first half of the week. South winds will begin to increase significantly around midday. Expect a high temperature at 8500' around 29 degrees and 1 to 3" of snow is likely in the afternoon. It looks very snowy in the next couple days, with southwest wind and 2 to 3 feet of snow likely at upper elevations by Tuesday morning.

general announcements

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

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.