Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Wednesday - January 6, 2016 - 7:05am
bottom line

MODERATE (Level 2): Heightened wind slab avalanche conditions exist on recently drifted slopes, and in some areas a triggered deep slab avalanche failing on a persistent weak layer remains a possibility. You might trigger a dangerous avalanche from a rocky area or where the slab layer is thin. Evaluate the snow and terrain carefully, make conservative decisions, and continue to avoid steep drifted slopes at upper elevations.




current conditions

There's an inch of new snow and it's 27 degrees at the Tony Grove Snotel at 8400'. There's 47 inches of total snow, containing 97% of average water content for the date. I'm reading 22 degrees at the 9700' CSI Logan Peak weather station, with 15 mph wind still from the south-southeast. The best riding I've found is in sheltered lower angled terrain. Sunny slopes have seen a few minor melts and refreezes, and may be a bit crusty. Off the wind damaged ridge-lines you can still find pretty good settled powder riding conditions in many areas, but I've started sinking into sugary faceted snow again where it's shallow or rocky. Time (and settlement) is gradually healing the deep instabilities in the snowpack and dangerous avalanches continue to become less likely in the backcountry. Even so, you might still trigger large and scary avalanches in some areas, and riders proved this, triggering some impressive and fairly extensive avalanches near Danish Pass above Bear Lake late last week or over the weekend.

Obviously, avalanches are possible in some areas. These recent sled triggered slides, north of the State Line in the Danish Pass and St. Charles Canyon Areas failed just above and ran on a rime-crust from December 8 and 9. (1-4-2016)


recent activity

Still scratching my head thinking about the recent sled triggered avalanches just north of the state line in the Danish Pass and St. Charles Canyon Areas. The very broad 2-foot-deep avalanches that appear sled triggered, failed on a thin layer of weak faceted snow on top of a rime or rain crust from early December. I'm unsure of the timing of these unreported avalanches, and it looks like someone had an interesting encounter with the serpent at some point around the New Year.

-Observers reported natural and triggered wind slab avalanche activity on New Years Day and over the weekend in the Tony Grove and Providence Canyon Areas. The avalanches were fairly shallow, soft, and generally manageable

Evidence of significant natural activity from the productive pre-Christmas storm is widespread across the Logan Zone. Most of the natural avalanches occurred early in the storm, and likely failed and ran above the Dec.8/9 rime-crust. But, there are also a few that appear to be a bit more recent, released on deeper faceted weak layers, and a few might have been remote triggered...

  • DB Bowl Avalanche: Here's a video observation looking at a recent natural Avalanche in Logan Dry Canyon.
  • I observed several large more recent avalanches in the upper Providence Canyon area on 12/26. I think these were Christmas Eve naturals, but they might've been remote triggered, unseen by riders in limited visibility. Video Report
  • On 12/19 an experience local rider was caught and carried through trees, mostly buried, trapped, injurred, and rescued from an avalanche he triggered above the Tony Grove Campground. Video Report

***To view our updated list of backcountry observations and avalanche activity from around Utah, go to our observations page

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

Southerly winds continue in the high country drifting the new snow as it accumulates. Expect fresh and developing wind slabs near ridge tops and in and around terrain features like gullies, sub-ridges, scoops, and rock outcroppings. In many cases, recent wind slabs may have formed on weak faceted or feathery snow that was previously on the snow surface. Several natural and triggered wind slab avalanches were reported in the Logan Zone over the New Years Weekend, and a few inches of accumulation + continuing south wind = new wind slabs in drifted terrain today.

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

Time, settlement, and sintering helped to stabilize the snow, and in many areas the slab layer is so thick that it would be very difficult for riders to trigger. But as recently proven near the Idaho state line, dangerous avalanches remain possible in some areas, and heightened avalanche conditions persist. Dangerous deep slab avalanches might be triggered from shallower areas on the slab, especially in outlying drifted terrain at upper and mid-elevations. In addition to deeply buried facets and depth hoar, we also clearly need to keep an eye on the weakness associated with the widespread December 8/9 crust layer.

***Pay close attention to signs of unstable snow like recent avalanches, whumpfing, and shooting cracks, and be willing to reevaluate your plans. In these conditions you could still trigger avalanches remotely, from a distance or worse, from below!

weather

Snow is likely today, with 1 to 3 inches of accumulation possible, a high temperature ay 8500' of around 30 degrees and continuing moderate south winds. A few more inches of accumulation is possible overnight, and accumulating snowfall should continue through the week. Looks like we might pick up 8 inches to a foot of total of new snow by the weekend...

general announcements

The CROWBAR backcountry ski race will be Saturday January 30. More info at http://CrowbarSkiRace.org.

Please submit snow and avalanche observations from your ventures in the backcountry HERE. You can call us at 801-524-5304 or email HERE, or include #utavy in your Instagram or Tweet us @UAClogan. To report avalanche activity in the Logan Area or to contact the local avalanche forecaster call me, Toby, at 435-757-7578. 

I'll update this advisory throughout the season on Monday, Wednesday, Friday, and Saturday mornings by about 7:30

This advisory is produced by the U.S.D.A. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist.