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Forecast for the Logan Area Mountains

Nikki Champion
Issued by Nikki Champion for
Monday, December 5, 2022
The avalanche danger is CONSIDERABLE where strong winds and recent snowfall have created dangerous avalanche conditions. Human-triggered avalanches are likely. Any natural or human-triggered avalanche can be 1-3' deep, and over a hundred feet wide.
Elevated conditions also exist in sheltered terrain and on steep lower and mid-elevation slopes where people could trigger small soft slab and loose snow avalanches

Evaluate snow and terrain carefully, make conservative decisions, and avoid slopes with recent deposits of wind-drifted snow steeper than about 30°. Low-angle terrain remains the safest, and best option today.
Low
Moderate
Considerable
High
Extreme
Learn how to read the forecast here
Special Announcements
Our annual party and fundraiser is coming up on December 6 in Logan at the Cache. 19th Annual Utah Avalanche Center Pray for Snow Party and Fundraiser information and tickets HERE.
Join the Utah Avalanche Center and the Division of Outdoor Recreation to celebrate the Fourth Annual Avalanche Awareness week, from December 4 - December 11. Click HERE to view the full list of events for the week.
A few highlighted events for the Logan area:
  • Join us Wednesday, December 7th at USU for a Know Before You Go. Find more info HERE.
  • Join us Saturday, December 10th at Beaver Mountain for FREE UAC and USU Beacon Clinic. Find more info HERE.
Weather and Snow
Dangerous avalanche conditions exist in the backcountry. Last week's heavy snow and drifting overloaded widespread slopes with buried persistent weak layers and poor snow structure. Dangerous human-triggered avalanches are likely on drifted upper and mid-elevation slopes. Nearly all parties have been reporting heart-stopping audible collapses or "wumpfs" and shooting cracks as they traveled through the new snow at mid and upper elevations. These are "bulls-eye" red flags indicating unstable snow and real potential for dangerous slab avalanches failing on a persistent weak layer.

This morning, skies are overcast. Remote weather stations at Tony Grove Lake and Franklin Basin have reported between 5-7" of new snow since yesterday morning. Temperatures are in the upper teens F to low 20s F, the wind has decreased since yesterday and is now blowing from the west-northwest between 10-20 mph with gusts near 30 mph.
Today will remain overcast this morning with light snowfall possible until noon with no additional accumulation expected. Skies will then become partly cloudy and temperatures will climb into the mid and upper 20s F, and winds will remain westerly averaging speeds of 10-20 mph, with gusts up to 30 mph at upper elevations.
Recent Avalanches
No new avalanches were reported in the backcountry yesterday, but we had an active weekend with many submitting recent activity. Find the whole list below:
  • Tony Grove Road - E Aspect - 6500' - Soft slab avalanche failing on SH buried 12" deep - 12/2
  • Logan Peak/Fair Grounds Bowl - E Aspect - 9500' - Hard slab avalanche failing on a buried weak layer of facets 2.5' deep - 12/2 (See image below list)
  • Beaver Creek Canyon - W Aspect - 7400' - Soft slab avalanche failing on a buried weak layer of facets - 12/2
  • Red Pine Ridge - E Aspect - 9000' - Cornice triggered hard slab avalanche failing on a buried weak layer of facets - 12/2
  • Three Terraces - E Aspect - 9000' - Cornice triggered hard slab avalanche failing on a buried weak layer of facets - 12/2
  • North Face of Providence Peak - NE Aspect - 9300' - Hard slab avalanche failing on a buried weak layer of facets 2' deep - 12/2 (See the second image below list)
  • Logan Dry Canyon - N Aspect - 7600' - Soft slab avalanche failing on surface hoar - 12/3
  • Mezzanine - NW Aspect - 7500' - Soft slab avalanche failing on a buried weak layer of facets 14" deep - 12/3
  • Mount Naomi Wilderness - W Aspect - 9200' - Hard slab avalanche failing on a buried weak layer of facets - 12/3
  • West side of Egan Basin - E Aspect - Soft slab avalanche failing on a buried weak layer of facets - 12/3
  • Grandfather Cornice - E Aspect - 9400' - Cornice triggered hard slab avalanche failing on a buried weak layer of facets 3' deep - 12/3 (See the third image below)
See our updated list of observed avalanches from across Utah HERE
Ad
Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
The situation is very simple - there is a persistent weak layer (PWL) of faceted snow from roughly 16 days of clear and cold weather in November that now has 1-3' feet of snow on top of it. Over the last few days, this layer has begun producing both small and large avalanches. As we continue to add more snow, and more wind to this weak layer we will only continue to see larger and more destructive avalanches occurring.
  • We've found buried soft sugary snow at all elevations and on slopes facing every direction. The persistent weak layer (PWL) problem has the potential to get worse as widespread slopes with poor snow structure are overloaded, and the problem is likely to be an issue for a while.
  • Areas plagued by a very sensitive PWL consisting of buried feathers of surface hoar are also widespread, but we've found them mostly in sheltered low and mid-elevationon terrain. Persistent weak layers consisting of surface hoar are notoriously tricky, often surprising and sometimes catching experienced avy pros off guard. Avalanches failing on buried surface hoar may occur on lower angled slopes than you might expect.
  • Red Flags indicating PWL instability will include audible collapses or wumpfs and shooting cracks. Slab avalanches failing on a buried persistent weak layer are likely to be remotely triggered from a distance, hopefully from above or from an adjacent slope, and not from below.
Last week's new snow fell on bare ground or very shallow snow on low and many mid elevation sunny slopes, (W, SW, S, SE) so the danger of avalanches is lower (Moderate), but potential might be higher for hitting rocks.

Video from our field day Saturday near White Pine Knob where we were able to find the weak faceted snow beneath the recent snowfall.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Over the last 24 hours, winds have been elevated, with gusts between 30-50 mph throughout the day yesterday. Any elevated winds today will continue to transport the 5-7" of new snow. People are likely to trigger dangerous slab avalanches of stiffer wind-drifted snow failing on a sugary buried persistent weak layer if they venture onto exposed upper elevation slopes. Drifts and wind slabs may be hidden under fresh powder. Natural avalanches are possible today as more fresh snow drifted onto steep overloaded slopes.
  • Wind slabs often form on the lee side of exposed ridges and in and around terrain features. Watch for and avoid drifts on gully walls, under cliff bands, along sub-ridges, in scoops, saddles, and sinks.
  • Drifted snow is stiffer and more compacted than non-drifted snow. Yesterday's strong winds created harder drifts (called hard slabs if they avalanche). Hard slabs are often stubborn, notorious for allowing people to get out on them before releasing, kind of like a mouse trap!
  • Slab avalanches of wind drifted snow failing on a persistent weak layer might be triggered remotely, from a distance, or even below!
  • Today you should avoid travel on or under steep slopes with deposits of wind drifted snow.
  • Freshly formed wind slabs can be quite sensitive and are often remotely triggered.
  • Shooting cracks in drifted snow are a sure sign of instability.

    In areas protected from the wind, you may be able to find an avalanche within the 5-7" of new snow. Watch for loose dry avalanches in steep protected terrain.
Additional Information
  • Take the all-new online avalanche courses the UAC built for Know Before You Go or take other online courses listed on the KBYG website (Develop skills -> Online Learning).
  • Get your avalanche rescue gear ready for winter. Put fresh batteries in your transceiver and update the firmware. Inspect your shovel and probe. Get your airbag backpack ready by possibly doing a test deployment and update the firmware if it is an electric version.
General Announcements
Please submit your observations from the backcountry HERE.
For a list of avalanche classes from the Utah Avalanche Center go HERE
For information on where you can ride your sled or snowbike, check out this map of the winter travel plan for the Tony Grove and Franklin Basin Areas HERE.
The Tony Grove Road and other forest roads in the Logan Ranger District are not maintained for wheeled vehicles in the winter.
This information does not apply to developed ski areas or highways where avalanche control is normally done. This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.