Issued by Toby Weed on Friday morning, December 9, 2022
A quick hitting and blustery storm will cause significant drifting and increasing avalanche danger at upper elevations. Currently, there is MODERATE danger at all elevations, and people could trigger dangerous avalanches in the backcountry. Periods of heavy snow and drifting from west winds will elevate the danger. Heightened avalanche conditions already exist because of a widespread buried persistent weak layer and a growing slab of stiffer snow above it. Areas with more dangerous conditions exist on drifted upper elevation slopes, where people could trigger 1-3' deep hard slab avalanches of previously drifted snow as well as softer slab avalanches of today's freshly wind drifted snow.
Thanks for showing up Tuesday night and supporting the UAC. It was great to see everybody at the Cache! You made our annual Pray for Snow party/fundraiser a big success.
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.
The Saturday Beacon Clinic location has been moved. Due to the early opening of Beaver Mountain and adequate snow in the valley, the clinic will be held at USU Aggie Legacy Fields on the north side of the USU ARC. Parking is to the east of the fields.
Weather and Snow
Elevated avalanche conditions exist at all elevations in the backcountry, and drifting from today's quick hitting storm will cause increasing danger on upper elevation slopes. Last week's heavy snow and drifting overloaded many slopes plagued by buried weak layers and poor snow structure. Dangerous human-triggered avalanches remain possible for people to trigger, especially on previously drifted upper and mid-elevation slopes. Fresh and forming drifts today could be very sensitive and we can expect a rising danger of people triggering small avalanches of wind drifted snow. It's possible that a small avalanche overrunning a slope with poor snow structure could step down into sugary November snow and create a much larger hard slab avalanche
Although much less frequently in the last few days, observers continue to report localized audible collapses or "wumpfs" from across the zone. Collapsing indicates unstable snow and real potential for dangerous slab avalanches failing on a buried persistent weak layer.
It is snowing in the mountains this morning, and a quick hitting storm is expected to bring 4 to 8 inches of accumulation to upper elevation slopes. Snow could be heavy at times. Expect high temperatures at 8500' around 20° F, dropping to around 12° F in the afternoon. It will be rather breezy, with 15 to 25 mph west winds, and gusts around 35 mph. Avalanche conditions will surely worsen this weekend, as a prolonged period of snowy weather is expected Saturday night through early next week, with potential for substantial accumulations.
Recent Avalanches
No new avalanches were reported in the backcountry since a pretty active weekend when several remotely triggered and some large natural avalanches were reported.
Several people ventured into the backcountry terrain on the Beaver Backside on Wednesday and some reported collapsing, but no avalanches were reported from the area.
Remember, when you leave the ski area, you are entering the backcountry and you could trigger dangerous avalanches.
***See our updated list of observed avalanches from across Utah HERE
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. 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-elevation 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 a persistent weak layer instability will include audible collapses or wumpfs and shooting cracks. 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, hopefully not from below.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Expect rising danger of avalanches of wind drifted snow as fresh snow is drifted into upper and mid-elevation avalanche starting zones. Avoid fresh drifts on the lee side of major ridges and in and around terrain features like gully walls, under cliff bands, scoops, saddles, and sub-ridges.
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.
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.
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.
