Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Saturday - February 3, 2018 - 6:53am
bottom line

Areas with heightened avalanche conditions exist in the backcountry. Cornice fall and wind slab avalanches are possible in drifted upper elevation terrain. Dangerous persistent slab avalanches are unlikely, but remain possible on isolated steep slopes with poor snow structure.

  • Evaluate snow and terrain carefully.
  • Avoid travel on or under large ridge top cornices and steep drifted slopes.
    I will update this advisory on Monday, 2/5/18



special announcement

The latest UAC podcast - "Recreating Like a Pro - A Conversation with IFMGA guide Anna Keeling" is live. This podcast will be ideal for anyone looking to pick up some tips and tricks from a professional mountain guide for recreating in the winter backcountry environment.​
current conditions

The Tony Grove Snotel at 8400' reports 34°F, and there's 56 inches of total snow at the site containing 87% of normal SWE (or Snow Water Equivalent). It's 33°F at UDOT Hwy 89 Logan Summit and a northwest wind is blowing 10 to 15 mph and gusting to 43 mph this morning. Heightened avalanche conditions exist on drifted upper elevation slopes where human triggered cornice falls and wind slab avalanches are possible. Dangerous persistent slab avalanches continue to become less likely but remain possible slopes plagued by poor snow structure. It rained Saturday night and there's a thick and brittle translucent ice-crust on the snow surface at upper and mid elevations in the Bear River Range.

recent activity

Thursday, we could see evidence of some recent sizable cornice falls and resulting natural wind slab avalanches off the south ridge of Mt. Magog.
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

An incessant and strong westerly wind continues to drift snow at upper elevations, in some cases stripping Saturday night's rime-crust off windward slopes and open fetch areas, forming stiff wind slabs in lee slope deposition areas, and building huge cornices along north-south oriented ridge lines. The widespread rime or rain-crust is holding snow in place and preventing drifting in most places, especially at mid and lower elevations. Human triggered cornice fall and wind slab avalanches are possible, and some large natural cornice falls are possible as strong westerly winds continue into the weekend.

  • Watch for and avoid drifted snow on steep lee slopes and in and around terrain features like sub-ridges, gullies, scoops, and rock outcrops.
  • Avoid travel on or under large ridge top cornices, which might break further back than expected and could 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

Widespread buried faceted layers appear dormant now, and dangerous persistent slab avalanches are becoming less and less likely to trigger with time. Even so, avalanches stepping into old snow remain possible on steep slopes, especially those with shallow snow and poor snow structure. We continue to see full propagation and clean, quality 1 shears in some of our test pits, and there have been a couple reports in the past two days of parties triggering large audible collapses or whumpfs in the North Sinks, Swan Flat Rd Area.

  • Some drifts likely formed in areas with poor snow structure, overloading weak faceted snow, and dangerous persistent slab avalanches involving previously drifted snow are possible.
  • Pay attention to possible signs of instability like cracking and whumpfing or collapsing, but remember these signs aren't always present when avalanches are triggered, so you have to dig down into the snow to find poor snow structure.
  • Persistent slab avalanches are often triggered from low on the slope, and might be triggered remotely, from a distance or below.​
weather

High pressure aloft parked off the west coast will maintain a somewhat moist northwest flow across the Great Basin this weekend. The flow aloft will turn more northerly early next week, allowing a stronger weather disturbance to take aim on Utah early in the week.

  • Today: A chance of snow before 11am, then a chance of snow showers after 11am. Cloudy, with a temperature falling to around 27 by 5pm. Breezy, with a west wind 25 to 28 mph, with gusts as high as 41 mph. Chance of precipitation is 30%. Total daytime snow accumulation of around an inch possible.
  • Tonight: A chance of snow before 11pm, then a chance of snow showers after 11pm. Cloudy, with a low around 28. Windy, with a west wind 25 to 31 mph, with gusts as high as 45 mph. Chance of precipitation is 30%. New snow accumulation of less than one inch possible.
  • Sunday: A 40 percent chance of snow showers. Cloudy, with a high near 36. Breezy, with a west wind 15 to 23 mph. New snow accumulation of around an inch possible.
general announcements

We have discount lift tickets for Alta, Snowbird, Brighton, Solitude, Snowbasin,and Beaver Mountain. Details and order information here. All proceeds from these 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

Episode 3 of the UAC podcast is live. We talk with UDOT Avalanche Program Supervisor Bill Nalli on how he and his teams keep the Greatest Snow on Earth from avalanching over the open roads and highways of the state. 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 tweet or 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.