Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Monday - January 30, 2017 - 7:02am
bottom line

The snow is stable and avalanches are unlikely on most slopes, but heightened avalanche conditions exist in some areas, with triggered persistent slab, wind slab, and loose wet avalanches possible. Persistent slab avalanches, 2' deep, are possible at mid and lower elevations on slopes with buried surface hoar and in sunny terrain with buried facets above a sun-crust. Evaluate snow and terrain carefully, avoid steep drifted terrain and sunny slopes with saturated surface snow.




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current conditions

The 8400' Tony Grove Snotel reports 25 F and 99" of total snow containing 155% of average SWE (Snow Water Equivalent.) It's 25 F at the CSI Logan Peak weather station at 9700', and the wind is blowing from the southwest at 22 mph.

You'll find much nicer weather, clean air, warmth, sunshine, and nice powder riding conditions in the mountains above the valley murk. South facing slopes are sun-affected and the snow surface is either crusty or saturated, but fine settled powder still exists on many slopes in the zone. Lots of people got out this weekend and no significant avalanches were reported. The snow appears stable in most places, but areas with unstable snow exist. Triggered avalanches, 2' deep, on buried surface hoar are possible on mid and lower elevation slopes. Collapses, cut-bank activity, and snowpit tests this weekend indicate avalanche potential. Over the weekend, I found poor snow structure with buried surface hoar and weak facets capping a sun-crust in sunnier areas at mid and lower elevations on west and southwest facing slopes in East Wood Camp in the the southern Bear River Range.

Poor snow structure and triggered avalanche potential exist on slopes with buried surface hoar or sugary facets capping a sun-crust. (1/29/17)
recent activity
  • I triggered a large audible collapse or woompf in East Wood Camp on a west facing slope at 6300' on Saturday. Collapses indicate unstable snow, and I found buried weak snow of surface hoar and small facets capping a thin sun-crust 2' deep.
  • Ski cuts yesterday in unsupported snow above recently cut cat-road triggered localized 2' deep soft slabs on layer of buried surface hoar.

Trent looks at a recent triggered avalanche in the Park City backcountry. The triggered persistent slab avalanche failed on facets capping a sun-crust on a east-southeast facing slope.

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
  • With last Monday's storm, a couple feet of snow fell on weak surface snow consisting of surface hoar and/or small-grained sugary facets.
  • Triggered persistent slab avalanches around 2 feet deep, and a few hundred feet wide are possible.
  • Recent triggered avalanches in the Park City area failed on this weak layer, which also exists in the Logan Zone.
  • Buried surface hoar exists mainly in sheltered mid and lower elevation terrain, and we've found it on east, north, and west facing slopes.
  • Avalanches on surface hoar have a nasty reputation for failing on low angled and low elevation slopes.
  • A weak layer of small facets on top of a sun-crust plagues some sunny mid elevation slopes.
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

Heightened wind slab avalanche conditions exist in drifted upper elevation terrain.

  • Southwest winds likely created fresh wind slabs in terrain features and lee slope avalanche starting zones.
  • 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.
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

Solar warming will cause a heightened danger of loose wet avalanches during the middle of the day on sunny slopes in sheltered terrain.

weather

A strong mid level ridge will remain in place across the region through midweek. A series of weak weather systems will cross the area late in the week through next weekend.

Today: Mostly sunny, with a high near 33. West wind 14 to 18 mph.
Tonight: Partly cloudy, with a low around 21. West wind 15 to 20 mph.
Tuesday: Increasing clouds, with a high near 34. West wind around 21 mph.
Tuesday Night: Cloudy, with a low around 21. West wind around 20 mph.

general announcements

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

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.