Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Saturday - January 30, 2016 - 7:22am
bottom line

HIGH (level 4): Avoid travel in backcountry avalanche terrain. We recommend you stay off of and out from under obvious and historic avalanche paths and slopes steeper than about 30 degrees at all elevations. Heavy snow, strong southwest winds, and a bit of rain-on-snow overnight caused the avalanche danger to rise significantly. Very dangerous avalanche conditions exist with both human-triggered and natural avalanches likely. Continuing heavy snowfall and northwest winds during the day today will probably cause the danger to increase further and become more widespread.
avalanche warning

HE FOLLOWING MESSAGE IS TRANSMITTED AT THE REQUEST OF THE FOREST SERVICE UTAH AVALANCHE CENTER. THE FOREST SERVICE UTAH AVALANCHE CENTER IN SALT LAKE CITY HAS ISSUED A BACKCOUNTRY AVALANCHE WARNING.

* TIMING...THROUGH 6 AM SUNDAY MORNING.

* AFFECTED AREA...ALL THE NORTHERN MOUNTAINS OF UTAH.

* AVALANCHE DANGER...IS HIGH...NATURAL AND HUMAN TRIGGERED SLIDES ARE CERTAIN TODAY.

* IMPACTS...DANGEROUS AVALANCHE CONDITIONS EXIST. TRAVELERS SHOULD AVOID STEEP SLOPES AND AVALANCHE RUNOUT ZONES...INCLUDING LOW ELEVATION SLOPES.

BACKCOUNTRY TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENDED. BACKCOUNTRY TRAVELERS SHOULD CONSULT WWW.UTAHAVALANCHECENTER.ORG OR CALL 1-888-999-4019 FOR MORE DETAILED INFORMATION.
current conditions

Very dangerous conditions exist in the backcountry, and people should avoid travel in avalanche terrain today. We recommend you stay off of and out from under obvious or historic avalanche paths and slopes steeper than about 30 degrees. Natural and human triggered avalanches are likely. The temperature is 23 degrees and this morning there's several inches of heavy new snow (with a gain of 1.5 inches of water in the last 24 hours) at the 8400' Tony Grove Snotel. I'm reading 75 inches of total snow, containing 107% of average water content for the date. The 9700' CSI Logan Peak weather station reports 17 degrees and fairly strong southwest winds overnight, currently the wind is from the northwest averaging about 18 mph. Most stations in the range are reading between 1.3-1.5" of water in the past 24 hrs. It'll be a good day to ride on established trails and in lower angled meadows, but you should avoid and stay out from under steep hills. Beaver Mountain will be a great non-backcountry powder option for skiers and riders today, with 8" of new snow reported overnight.


recent activity

A skier triggered and then escaped this shallow wind slab avalanche in Wildcat Bowl in the Wood Camp Area on Wednesday (1-27-16). Several other similar (apparently manageable) avalanches were triggered by people locally in the past few days.

  • A skier triggered and was able to get out in front of a shallow wind slab avalanche in the Wood Camp Area on Wednesday, 1-27-16. Report is HERE
  • Observers report seeing several recent (and fairly small) rider and skier triggered avalanches in the Tony Grove Area. These manageable wind slabs on steep north through east facing slopes above around 8200' in elevation were around a foot deep and the largest around 50' wide. Report HERE
  • It appears there was a fairly widespread natural cycle with similar wind slab activity after last Sunday's storm, and I noticed recent natural activity in the Steep Hollow Area on Tuesday. Report HERE
  • A sledder triggered but was not caught in a good sized avalanche in the Fairgrounds on the east side of Logan Peak last weekend. Report ....HERE
  • Including this one, we know of 10 other large unintentionally triggered avalanches in the Logan Zone from last week(1-16 through 1-24)! These were all probably kinda close calls!
  • A video posted on Facebook from a large sled triggered avalanche (1-19-16)in Christmas Tree Bowl is .....HERE

***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

Soft storm slab avalanches including heavy new snow are likely in steep terrain today as additional new snow piles up on preexisting weak surface snow.

  • We've noticed the development of small sugary faceted snow and areas with feathery surface hoar on the snow surface in the past few days. If the weak surface snow was buried intact by yesterday's light snow before being destroyed by warmth, rain, or wind, it is likely to be the failing layer for today's storm slabs. The buried weak snow may also be a longer lasting persistent weak layer.
  • Natural avalanche activity is most likely today during periods of particularly heavy snowfall.
  • Strong southwest winds accompanied heavy snowfall last night and drifting probably occurred well off the major ridge tops. Watch for and avoid slopes with recent stiffer deposits of drifted snow, particularly near ridge tops and in and around terrain features like gullies, sub-ridges, scoops, and rock outcroppings.

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

Heavy new snow, rain-on-snow at lower elevations, and strong winds overloaded a complex snowpack, with existing buried persistent weak layers in some areas and still weak basal layer depth hoar in others.

  • Triggered and natural deep slab avalanches are likely in some areas. Snowpit tests this week showed reasonable stabilization of the buried January persistent weak layers in most areas. But, I was able to find moderate failures and slab propagation in some places and weak snow structure mainly in areas where the slab from last week's snow is 2' deep or less, including in shallow lower and mid elevation areas and on generally south facing slopes.
  • In areas with particularly poor snow structure, the weak faceted snow in the basal layers of the snowpack may be reactivated by the added weight of last night's and today's accumulating snow. Dangerous and destructive​ deep slab avalanches involving old snow and failing on sugary faceted snow or depth hoar occurred and are possible, especially in areas with shallow overall snow cover. Deep slab avalanches may pull out saturated snow at lower elevations, and large long running natural avalanches are possible on big slopes

***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 trigger avalanches remotely, from a distance or worse, from below!
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

Cooling temperatures today will help with this problem, but rain-on-snow overnight up to around 7500' in elevation saturated the preexisting shallow snow at lower elevations, and natural wet activity is likely in some areas today. Avoid lower elevation terrain traps, and don't hang out below steep snow covered slopes like those above the Logan River Trail and my favorite mid-canyon fishing holes... Wet natural activity is most likely at low elevations in the foothills and near canyon mouths in the front canyons like lower Logan, Green, and Providence, places where you might normally take the dog for a walk or the kids sledding...
weather

There is an Avalanche Warning as well as a Winter Storm Warning in effect today. These both affect all the mountains of northern Utah and Southeast Idaho. We will see continued snowfall today with an additional 4-8" of accumulation. It will be blustery with northwest winds ranging from 18-23 mph, with gusts in the 30's. As the front moves through the state, expect temperatures in the Logan area mountains to fall in the afternoon into the teens and snowfall to taper by the end of the day. It'll be mostly cloudy tonight, with a chance for lingering snow showers, moderate west-northwest wind, and a low temperature at 8500' of around 7 degrees. The next storm system moves into the state on Sunday but is expected to mostly impact central and southern Utah.

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.