Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Friday - January 27, 2017 - 7:04am
bottom line

Heightened avalanche conditions exist at all elevations, with triggered persistent slab, wind slab, and loose wet avalanches possible. More dangerous conditions, areas with CONSIDERABLE avalanche danger exist at mid and lower elevations on slopes with buried weak surface snow. Evaluate the snow carefully, make conservative decisions, avoid steep slopes with drifted or sun-warmed snow.




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current conditions

Fine deep powder riding conditions exist across the Logan Zone, but rapid accumulation of 2 to 3 feet of snow on weak surface snow Monday and Monday night created dangerous avalanche conditions. With help from time and settlement the snow becoming more stable on most slopes, but areas with unstable snow exist, and two unintentionally triggered avalanches were reported yesterday. The 8400' Tony Grove Snotel reports an inch of new snow, and at 3:00 yesterday afternoon there was 110" of total snow at the site containing 161% of average SWE (Snow Water Equivalent.) I'm reading negative 11 F at 6:00 AM at the UDOT Hwy 89 Summit weather station, with calm winds. It's 2 F at the CSI Logan Peak weather station at 9700', and the wind sensor is encased by rime-ice and not working. The wind is blowing from the northwest at 17 mph on Ogden Peak.

Eric and Amy Flygare found deep powder near Tony Grove Lake on Wednesday.

recent activity
  • Yesterday (1/26/17); A snowboarder unintentionally triggered a 2.5' deep, 20' wide avalanche on a north facing slope at 8300' just south of Tony Grove Lake. A sledder reported a fresh triggered avalanche on the Providence Quarry slag pile, 1 to 3' deep and about 70' wide.
  • Numerous sizable and long-running natural avalanches occurred during Monday's storm in the Wellsville Range. Several are visible from Hwy 89/91 in the Dry Lake section of Sardine Canyon.
  • Natural storm snow avalanches caused UDOT to close Hwy 89 in Logan Canyon Monday. The canyon was reopened on Tuesday.
  • Wednesday, a skier was caught and carried in a slide on Mt Aire, which is just west of Lambs Canyon along I-80. The avalanche failed on buried surface hoar and the snow setup is similar on many slopes in 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
  • Tons of recent snow accumulated and was drifted onto weak surface snow consisting of surface hoar and/or small-grained sugary faceted snow.
  • Many of the recent triggered and natural avalanches in the Ogden and Salt Lake area mountains failed on this weak layer, and it is widespread in the Logan Zone as well.
  • Avalanches failing on surface hoar have a nasty reputation for occurring on unexpectedly low angled or low elevation slopes and catching people off-guard.


  • Feathery surface hoar crystals like these from last week in the Wellsville Range are formed by frost growing on the snow surface.


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 terrain.

  • Drifts from Monday will be buried and hidden by several inches of powder that fell during calmer conditions.
  • At upper elevations, northwest winds drifted the light surface snow into terrain features and lee slope avalanche starting zones, creating fresh wind slabs.
  • 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

Despite cold air temperatures, solar warming could cause a danger of loose wet avalanches on sunny slopes in sheltered terrain.

weather

Strong high pressure aloft along the west coast will expand east across the Great Basin this weekend. Expect sunny conditions in the mountains and the development of haze in the valleys. It'll be sunny today, with a 8500' high temperature of 19 F and a 10 mph northwest wind. It will be mostly cloudy tonight with a low temperature or 14 F and 10 mph northwest wind. Tomorrow will be sunny with a high temperature of 25 F and a 10 mph northwest wind.

general announcements

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

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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.