Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Saturday - January 27, 2018 - 7:16am
bottom line

Pockets with dangerous avalanche conditions exist on drifted upper elevation slopes in the backcountry. Human triggered wind slab avalanches are likely in some areas, and dangerous persistent slab avalanches are possible. Very nice powder riding conditions exist in sheltered terrain, on lower angled slopes and at lower elevations.

  • Evaluate snow and terrain carefully, and make conservative decisions.
  • Avoid travel in drifted upper elevation terrain and steep rocky areas with shallow snow cover.
    I will update this advisory on Monday morning, 1/29/18, before about 7:30.



special announcement

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!
current conditions

The Tony Grove Snotel at 8400' reports 3 more inches of light new snow and 12" from the storm with 1.1" SWE (or Snow Water Equivalent). It's 18°F, and there's 63 inches of total snow at the site containing 91% of normal SWE . It's 16°F at UDOT Hwy 89 Logan Summit and it's nice and calm this morning. South winds are expected to pick up again today, and resulting drifting will build existing slabs and create more in exposed upper elevation terrain. Pockets with dangerous wind slab conditions exist, and human triggered avalanches are likely. Most sheltered slopes and those at lower and mid elevations are showing good stability despite widespread buried layers of weak faceted snow. We found very nice fast powder conditions yesterday, and it was especially nice on lower angled slopes.
recent activity

A few small natural and intentionally triggered wind slab avalanches were reported from the Franklin Basin Area earlier this week.

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

Wind slab avalanches, made up of drifted snow are likely in exposed upper elevation terrain. With lots of nice powder to drift, continuing fairly strong south winds today will build existing slabs and create fresh ones, which are likely be sensitive to human triggering.

  • Watch for and avoid drifted snow on steep lee slopes and in and around terrain features like sub-ridges, gullies, scoops, and rock outcrops.
  • Some drifts likely formed in areas with poor snow structure, overloading weak faceted snow, and dangerous persistent slab avalanches involving old snow are possible.
  • Loose avalanches or sluffs consisting of fresh snow are possible on steep slopes in more sheltered terrain.
  • A ride in even a small avalanche could be particularly dangerous in areas with shallow snow, due to the potential for being dragged through rocks.
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

Our snowpit test results show pretty good stability currently, despite the widespread existence of very weak buried faceted snow. Even so, dangerous triggered persistent slab avalanches are possible on steep slopes, especially those with shallow snow and poor snow structure. The faceted layers appear dormant, but a new load from the recent storm may reactivate buried weak layers in some areas this weekend, especially on drifted lee slopes.

  • 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 might be triggered remotely, from a distance or below.
  • Persistent slab avalanches are often triggered from low on the slope.

Paige took pictures of these well developed and chained facets, which are widespread in Providence Canyon (1/24/18).

weather

A couple of weak weather systems will brush by northern Utah over the weekend. High pressure aloft will build into the region early next week bringing mild weather, followed by a dry cold front Wednesday.

  • Today: Snow likely, mainly after 11am. Cloudy, with a high near 26. Breezy, with a south wind 16 to 26 mph, with gusts as high as 40 mph. Chance of precipitation is 70%. Total daytime snow accumulation of around an inch possible.
  • Tonight: A 50 percent chance of snow. Cloudy, with a temperature rising to around 28 by 3am. Breezy, with a southwest wind 21 to 25 mph, with gusts as high as 39 mph. New snow accumulation of 1 to 3 inches possible.
  • Sunday: A 50 percent chance of snow. Mostly cloudy, with a high near 32. Breezy, with a west wind 21 to 26 mph decreasing to 10 to 15 mph in the afternoon. Winds could gust as high as 40 mph. New snow accumulation of 1 to 2 inches possible.
general announcements

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.

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.

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

EMAIL ADVISORY: If you would like to get the daily advisory by email you will need to subscribe here.

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.