Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Saturday - December 23, 2017 - 6:53am
bottom line

The avalanche danger will rise today with additional snow and drifting from strong west winds. Heightened wind slab avalanche conditions already exist and a CONSIDERABLE danger will likely develop on drifted upper elevation slopes.

  • By this afternoon, we could see dangerous conditions, with human triggered avalanches likely.
  • Evaluate the snow and terrain carefully, make conservative decisions, and avoid steep drifted slopes.



current conditions

The avalanche danger will rise in the backcountry as snow from today's storm rapidly accumulates and is drifted into avalanche starting zones by strong west winds. The Tony Grove Snotel at 8400' reports 6 inches of new snow overnight, with .8" SWE (Snow Water Equivalent). It's 22°F at the site and there's 33" of total snow containing 80% of average SWE It's 16°F at the 9700' CSI Logan Peak weather station, with west-southwest wind currently blowing around 25 mph, and gusting to 42 mph.

  • There is more total snow and better coverage in the central and northern Bear River Range and at upper elevations.
  • Shallow early season snow conditions exist, and hitting rocks or stumps is a significant hazard. Travel cautiously and keep your speed down.
  • The Tony Grove Road is not maintained for wheeled travel in the winter.

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

Across the Logan Zone, wind slabs are forming today on weak preexisting snow. Heightened wind slab avalanche conditions already exist in exposed terrain at upper and mid elevations, and the danger will rise with continued snow and drifting from strong west winds. Dangerous conditions are likely to develop, with human triggered avalanches becoming likely on drifted upper elevation slopes.

  • Wind slabs, consisting of stiffer, drifted snow may be chalky in appearance and might produce hollow sounds.
  • Avoid fresh drifts in steep terrain near ridges and in and around terrain features like gullies, saddles, rock bands, scoops, and sub-ridges.
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

As the fresh Christmas snow stacks up on slopes plagued by very weak sugary or faceted snow, storm snow avalanches will be possible even in sheltered areas. The problem is, slopes might be subject to gradual loading in the next several days, and the slow increase in danger is liable to catch people off-guard.

  • Pay attention to possible signs of instability like cracking and whumpfing or collapsing.
  • Avalanches might be triggered remotely, from a distance, or worse, from below.
  • Sluffs or avalanches entraining loose snow are possible in steep terrain.
  • A ride in even a small avalanche could be particularly dangerous now due to hard underlying snow and real potential for being dragged through rocks or deadfall below.
weather

A series of weather systems will cross northern Utah this weekend into early next week.

  • 4 to 8 inches of additional snow is possible today. It will be very windy, with a west wind 28 to 33 mph, and gusts as high as 47 mph. High temperatures at 8500' will be around 27°F.
  • It'll be partly cloudy tonight, with a low around 7°F and wind chill values as low as -7°F. Northwest winds will blow 20 to 25 mph with gusts as high as 40 mph.
  • Snow is likely to develop again tomorrow afternoon, with 1 to 2 inches possible. Expect increasing clouds, a high temperature around 25°F and 7 to 11 mph west-southwest wind.
  • 4 to 8 inches are possible Sunday night with more west wind, and snow will probably continue well into Christmas Day...
general announcements

Don’t know what to buy your favorite skier for Christmas? Discount lift tickets for Alta, Snowbird, Brighton, Solitude, Deer Valley, Snowbasin, and Beaver Mountain are now available, donated by the resorts to benefit the Utah Avalanche Center. Details and order information here. These make a great holiday gift and all proceeds go towards paying for avalanche forecasting and education!

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

Go HERE for a list of UAC classes.

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

Benefit the Utah Avalanche Center when you shop from Backcountry.com or REI: Click this link for Backcountry.com or this link to REI, shop, and they will donate a percent of your purchase price to the UAC. Both offer free shipping (with some conditions) so this costs you nothing!

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.

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.