Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Wednesday - March 7, 2018 - 6:24am
bottom line

Heightened avalanche conditions exist in drifted terrain, and the danger is MODERATE. Human triggered cornice falls, wind slab avalanches, and dangerous persistent slab avalanches are possible. Solar warming will cause an increasing danger of loose wet avalanches on sunny slopes.

  • Evaluate snow and terrain carefully.
  • Avoid and stay out from under big cornices, steep drifted terrain, and sunny slopes with saturated surface snow.

I will update this advisory on Friday morning, 3/9/18




special announcement

Episode 6 of the UAC podcast "A Conversation with Tom Kimbrough, Hemingway of the Wasatch" is live. We explore ideas about lifetime exposure to risk and what role Buddhism has played in his life as a climber, skier, and soon-to-be octogenarian. We talk about what has changed over the years in snow science and the role of mentorship in the world of avalanche forecasting and other professions and pursuits. Check it out on ITunes, Stitcher, the UAC blog.
current conditions

There's still great powder conditions in north facing terrain, but strong March sun moistened the snow on sunny slopes and at lower elevations, so there will be a widespread variable melt-freeze crust this morning. There are still areas with poor snow structure and potential for avalanches failing on buried persistent weak layers in the Logan Zone, but we've found good stability in the past few days, with only loose sluffs and cornice falls reported and observed. Heightened avalanche conditions exist in drifted terrain, and solar warming will soften the crust and once again create an increasing danger of loose wet avalanches on slopes with saturated surface snow.

  • At midnight, the Tony Grove Snotel at 8400' reported 17°F, and 76 inches of total snow, with 87% of normal SWE.
  • It's -1°F at the UDOT Hwy 89 Logan Summit this morning, and a east wind is lightly blowing 3 to 4 mph.


Drifting over the weekend built out large cornices on the major ridges. You should avoid these as they can break further back than expected.
recent activity

Somehow Trent caught the action yesterday, as a rider was caught and carried by a large avalanche in American Fork Canyon in the Wasatch Range. The report is HERE

We observed only minor natural cornice falls, very shallow soft slabs, and loose dry avalanches in the Logan Zone in the past few days. It's been a week since any significant avalanches were reported, and clearing yesterday did not show much in the way of recent natural activity.

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

Human triggered avalanches and cornice falls are possible in drifted upper elevation terrain. Wind slabs from this weekend may be obscurred by several inches of powder that fell since the winds moderated. Those that I found yesterday appeared pretty well locked in place, but beware of steep drifted slopes.

  • Watch for and avoid drifted snow in and around terrain features like cliff bands, gullies, scoops, and sub-ridges.
  • Wind slabs will be found on the lee side of major ridges, on slopes below cornices, in saddles, and downwind of open fetch areas.
  • Avoid ridge-top cornices, which often break further back than expected and can trigger avalanches on drifted slopes below.
  • Some wind slab avalanches could step down to buried weak faceted layers.

I got fooled and dropped a few feet by this somewhat stubborn cornice in the saddle in the backcountry on the south ridge of Beaver Mt yesterday.
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 persistent slab avalanche conditions exist, especially on slopes with shallow overall snow cover. We've found shallow snow and poor snow structure recently in shady, mid-elevation, forested, and windward terrain, with particularly eye-opening test results on west and north facing slopes. If you sink deeply into loose sugary snow, you've found poor snow structure, but in many areas you have to dig a snowpit to know.

  • Avoid steep rocky slopes with shallow snow cover and poor snow structure.
  • Persistent slab avalanches might be remote triggered, from a distance or below.
  • Cracking and collapsing or whumpfing are red flags indicating unstable snow.
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

Strong solar warming will soften the crust from yesterday and cause increasing danger of loose wet avalanches, entraining the weekend's snow. Wet sluffs can get pretty big and unmanageable on sustained steep slopes.

  • Roller balls, pinwheels, and natural sluffs indicate possible loose wet activity
  • It's time to move off slopes if you are sinking into slushy or sticky snow
weather

The broad area of high pressure aloft across the western states will generate a warming trend across Utah through the end of the week.

  • Today: Mostly sunny, with a high near 33. Southwest wind 5 to 8 mph.
  • Tonight: Mostly cloudy, with a low around 21. Southwest wind 8 to 10 mph.
  • Thursday: Partly sunny, with a high near 35. West southwest wind 13 to 18 mph.
general announcements

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.

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.

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.