Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Tuesday - February 20, 2018 - 6:59am
bottom line

The danger is CONSIDERABLE in the backcountry. Dangerous avalanche conditions exist at upper and mid elevations, with human triggered wind slab and persistent slab avalanches likely.

  • Evaluate snow and terrain carefully, and make conservative decisions.
  • Stay off and out from under steep drifted slopes.
  • There is less danger in sheltered, lower angled, and lower elevation terrain.
current conditions

Very nice deep powder riding and skiing conditions exist in the Logan Zone, but dangerous avalanche conditions exist on steep slopes.

  • The Tony Grove Snotel at 8400' reports -3°F and 74 inches of total snow, with 87% of normal SWE (or Snow Water Equivalent).
  • The station reported about 20 inches of settled new snow from the weekend storm, with 1.9" SWE.
  • I'm reading -5°F at the UDOT Hwy 89 Logan Summit sheds, and winds are mostly calm.
recent activity
  • A party of riders remote triggered a 400' wide avalanche from the ridge on a northeast facing slope at around 8900' near Gibson Basin yesterday. Nobody got caught and the avalanche apparently stepped down into old (faceted) layers.
  • There were a few smaller natural and sled triggered avalanches on Saturday, including this from an Instagram post.....View Post Here
  • Snowboarders unintentionally triggered, but escaped a slow moving soft slab avalanche in Miller Bowl above Tony Grove Lake Thursday, 2/15.
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

Dangerous avalanche conditions exist in drifted terrain.

  • Wind slabs are made up of stiffer, drifted snow. They can appear chalky and rounded and can make hollow drum-like sounds.
  • Avoid drifted snow in and around terrain features like sub-ridges, cliff bands, scoops, and gullies.
  • Avoid ridge-top cornices, which often break further back than expected. Wind slab avalanches are likely today under cornices.
  • In some areas, wind slabs formed on slopes with poor snow structure, and dangerous avalanches failing on persistent weak layers are possible.

  • Westerly winds picked up Saturday afternoon, drifting snow at upper elevations in the Wellsville Range
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

The weight of the storm snow might be enough to reawaken dormant buried faceted layers, and dangerous persistent slab avalanches are possible. Yesterday's large avalanche near Gibson Basin was triggered from a distance and stepped into old snow.

  • Continue to avoid steep rocky slopes with shallow snow cover and poor snow structure.
  • Avalanches could be remote triggered, from a distance or below.
  • Cracking and collapsing or whumpfing are red flags indicating unstable snow.


I found a couple buried weak layers made up of sugary faceted snow in snowpits near the Idaho State Line yesterday.
weather

A winter storm that impacted much of Utah will finally move east across the state today. A series of weather disturbances trailing this storm will impact the area for the middle to latter part of the work week.

  • Today: A 40 percent chance of snow showers. Mostly cloudy and cold, with a high near 7. Wind chill values as low as -17. West wind 10 to 14 mph. Total daytime snow accumulation of less than a half inch possible.
  • Tonight: Partly cloudy, with a low around -2. Wind chill values as low as -19. West southwest wind 9 to 14 mph becoming southeast in the evening.
  • Wednesday: A 20 percent chance of snow after 11am. Partly sunny, with a high near 15. Wind chill values as low as -13. Southeast wind 7 to 10 mph becoming southwest in the afternoon.
general announcements

Episode 5 of the UAC podcast To Hell in a Heartbeat - A Conversation With Tom Diegel and Matt Clevenger About the 12.26.08 Full Burial on Little Water is live. This podcast talks with Matt and Tom about their experience and the massive success of the To Hell in a Heartbeat video which has been viewed almost 3M times. Check it out on ITunes, Stitcher, the UAC blog, or wherever you get your podcasts.

We have discount lift tickets for Alta, Snowbird, Brighton, Solitude, Snowbasin,and Beaver Mountain. Details and order information here. All proceeds from your purchase go towards paying for avalanche forecasting and education.

The UAC Marketplace is online. The holiday auction is closed, but our online marketplace still has deals on skis, packs, airbag packs, beacons, snowshoes, soft goods and much more.

The UAC has new support programs with Outdoor Research and Darn Tough. Support the UAC through your daily shopping. When you shop at Smith's, or online at Outdoor Research, REI, Backcountry.com, Darn Tough, Patagonia, NRS, Amazon, eBay a portion of your purchase will be donated to the FUAC. See our Donate Page for more details on how you can support the UAC when you shop.

Benefit the Utah Avalanche Center when you buy or sell on eBay - set the Utah Avalanche Center as a favorite non-profit in your eBay account here and click on eBay gives when you buy or sell. You can choose to have your seller fees donated to the UAC, which doesn't cost you a penny Check it out on ITunes, Stitcher, the UAC blog, or wherever you get your podcasts.

Now is a great time to practice companion rescue techniques with your backcountry partners. Here's our rescue practice video.

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Remember your information can save lives. If you see anything we should know about, please help us out by submitting snow and avalanche observations. You can also call us at 801-524-5304, email by clicking HERE, or include #utavy in your Instagram.

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 occur.