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Forecast for the Logan Area Mountains

Toby Weed
Issued by Toby Weed on
Friday morning, December 16, 2022
Dangerous conditions and CONSIDERABLE avalanche danger exist on steep slopes in the backcountry at all elevations. This week's new snow and extensive drifting created thick slabs and overloaded slopes with poor snow structure. People are likely to trigger 1 to 3-foot-deep slab avalanches failing on a widespread buried persistent weak layer. Dangerous avalanches could be triggered remotely, from a distance, or below!
Conditions are less dangerous on southerly facing slopes at low and mid elevations, but avalanches remain possible on all backcountry slopes steeper than 30°
Careful snowpack evaluation, cautious route-finding, and conservative decision making are essential for backcountry travel.
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Learn how to read the forecast here
Special Avalanche Bulletin
DANGEROUS AND UNUSUAL AVALANCHE CONDITIONS WILL LAST THROUGH AT LEAST THIS WEEKEND. HEAVY SNOWFALL THIS PAST WEEK HAS CREATED DANGEROUS AVALANCHE CONDITIONS AT ALL ELEVATIONS. PEOPLE ARE LIKELY TO TRIGGER LARGE AND DANGEROUS AVALANCHES.
  • DON'T BE LURED BY THE BEAUTIFUL SUNNY SKIES AND FRESH POWDER INTO THINKING AVALANCHE CONDITIONS ARE SAFE WHEN THEY ARE NOT.
  • AVALANCHES CAN OCCUR IN LOW-ELEVATION FOOTHILLS, NOT FAR FROM PARKING AREAS AND TRAILHEADS.
Special Announcements
We have discounted Beaver Mountain tickets for sale. HERE..... Huge thanks to Beaver Mountain for supporting the work we do.
Weather and Snow
Very light powder has fallen in the past couple days, and the snow is so nice that it's easy to forget that conditions are dangerous on many slopes steeper than 30°. Earlier in the week, heavy snow and drifting overloaded many slopes plagued by buried weak layers and poor snow structure. Most recent backcountry observations included reports of audible collapsing or "whumpfs" and some included cracking in drifted terrain. These red flags indicate unstable snow and real potential for dangerous slab avalanches failing on a buried persistent weak layer.
A nasty persistent weak layer of loose sugary faceted snow is widespread across the zone.
Looks like a bit over 21 inches of new snow at the 8400' TGLU1 Snotel in the Central Bear River Range so far from this week's prolonged storm, with a bit more than four feet of total snow on the ground in most upper elevation terrain. Winds blowing from the northwest are blowing 20 to 30 mph this morning at the 9700' CSI Logan Peak weather station. Temperatures at 8500' are around 7° F this morning.
Expect mostly sunny but rather cold weather in the mountains today and this weekend. Today's 8500' high temperatures will be around 11° F, and northwest winds around 14 mph will create wind chill values as low as -19° F.
Tomorrow is expected to be mostly sunny but cold in the mountains, with high temperatures around 10° F and wind chill values as low as -16. Mostly sunny and cold conditions are expected through the weekend. Snowy conditions will return early next week.
Recent Avalanches
Thursday, I looked at a blown-in recent avalanche near the Bear Lake Overlook on Sunrise Hill (east facing, 7800'). The avalanche looks like it was triggered remotely since there were some snow bike tracks on the slope around 100' below. I have no idea when this occurred, but likely over the weekend after or during significant drifting from southerly winds.
Blown in evidence of a recent avalanche on Sunrise Hill that looks like it was triggered remotely by snow bikers.
On Tuesday a rider remotely triggered a slab avalanche failing on a sugary persistent weak layer near the ground in the Beaver Mountain backcountry.
Tracks show where a solo rider landed a jump and triggered this sizable slab avalanche that failed on a sugary persistent weak layer near the ground. (7000', east facing)
Wednesday, a solo skier was caught, carried, and partially buried in Neff's Canyon in the Salt Lake foothills. The skier sustained serious injuries in the 2' deep and ~200' wide avalanche that occurred at around 7200' in elevation on a northwest facing slope. (details and preliminary report HERE
A skier was seriously injured in an avalanche in Little Cottonwood Canyon in the Central Wasatch Range on Tuesday. Our preliminary report is HERE
***See our updated list of observed avalanches from across Utah HERE
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
We've found buried layers of sugary snow at all elevations and on slopes facing every direction. In many areas the basal layers of the snowpack are becoming loose and sugary. It's getting pretty easy to get the sled stuck if you sink and spin your track into the bottomless sugary snow. On Thursday, I triggered 3 large whumpfs on Sunrise Hill above Bear Lake Overlook on an east facing slope between 7600 and 7800'. After one collapse, a test pit near trigger point showed a fairly easily initiated propagating failure.
  • Red Flags indicating a persistent weak layer instability will include audible collapses or whumpfs and shooting cracks, but sometimes no red flags are apparent, and you have to dig down into the snow to find the sugary weak layer.
  • Slab avalanches failing on a buried persistent weak layer could be remotely triggered from a distance, and hopefully not from below.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
25 to 30 mph winds from the northwest are cranking along the ridges, and they continue to drift the light powder into avalanche starting zones at upper elevations. Sustained strong south winds last weekend picked up vast quantities of last week's nice light powder in lower angled terrain and meadows and drifted tons of snow into downwind deposition areas and avalanche starting zones. The drifting overloaded slopes with buried persistent weak layers, build stiffer slabs, and created dangerous avalanche conditions.
  • Many of last weekend's drifts are now hidden by this week's nice light powder.
  • Slabs of drifted snow formed and are still building on the lee side of major ridges, under cornices, and in and around terrain features like sub-ridges, saddles, cliff bands, and gully walls.
  • Today and this weekend we plan to once again stay off of and out from under all recently and previously drifted slopes in the backcountry steeper than about 30°.
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).
Remember, when you leave the ski area boundary, Beaver Mt or Cherry Peak, you are entering the backcountry, and you could trigger dangerous avalanches....
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.
  • Practice Companion Rescue with your backcountry partners.
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.
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.
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