Forecast for the Logan Area Mountains

Toby Weed
Issued by Toby Weed on
Wednesday morning, January 13, 2021
Blowing snow will limit visibility at upper elevations and cause increasing avalanche danger in the backcountry. Heightened avalanche conditions already exist on mid and upper elevation slopes, and people could trigger dangerous avalanches failing on a sugary persistent weak layer near the ground. There are still areas with CONSIDERABLE danger on drifted slopes facing northwest through southeast at upper elevations, where avalanches could be about 3-feet-deep and a few hundred feet wide. Avalanches could be triggered remotely, from a distance, or from below. You'll find safer conditions in lower angled, sheltered, and lower elevation terrain.

  • Cracking and collapsing indicate unstable snow.
  • Evaluate snow carefully, choose your route cautiously, and make conservative decisions.
  • Continue to avoid and stay out from under drifted slopes steeper than about 30 degrees.
Low
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Special Announcements
Sadly, I must report that on Friday, 1-8-2021, a 31-year-old male snowboarder from Clinton, Utah was killed in an avalanche in Dutch Draw in the backcountry near Park City. The final accident report is HERE.
Weather and Snow
ELEVATED AVALANCHE CONDITIONS EXIST IN THE BACKCOUNTRY. The snow pack is generally quite shallow in the Logan Zone and we have a serious problem with widespread very weak sugary snow and a dangerous persistent weak layer near the ground on most slopes. Due to the very shallow snow cover and cold mountain temperatures the sugary faceted snow crystals continue to grow, and on many slopes existing weak layers appear to be getting even weaker.

It's already snowing in the mountains this morning, and up to about 4" of accumulation is possible on upper elevation slopes today. It will also be quite blustery, with intensifying west winds, and blowing snow will limit visibility at upper elevations as well as cause increasing avalanche danger. 8500' temperatures are expected to be around 32°F. Although high pressure is dominating the weather pattern, it looks like we might see more weak storms in the Logan Zone, and there is potential for some more light snow over the weekend and early next week.
Recent Avalanches
  • A local rider was caught in a large avalanche that came from above, and he was completely buried under three feet of snow in the Steep Hollow Area Friday, 1-8-2021. Thankfully, he was rescued in time by his riding partners. Watch the video HERE
  • A rider reports that his party of sledders remotely triggered a large avalanche in Egan Basin Saturday, 1-9-2021.
  • There were four reported large remotely triggered avalanches in the Northern Bear River Range Friday, 1-8-2021, all triggered by sledders or snow bikers, and luckily from a distance.
  • Riders in upper Providence Canyon Wednesday remote triggered a few good sized avalanches from a good distance away in the flats...

A very wide avalanche was remotely triggered yesterday by riders near Bloomington Lake on Friday, 1-8-2021. It's a good thing that the avalanche happened before anybody was out riding on the slope.
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
The buried persistent weak layer problem involving sugary faceted snow is a very dangerous and notoriously tricky avalanche problem, and it is responsible for most fatalities, injuries, and close calls in the Logan Zone. Very weak sugary or faceted snow near the ground is widespread across the region, and people could trigger avalanches where a slab of more cohesive snow has formed on top of the weak snow.
  • Avalanches failing on a buried persistent weak layer might be triggered remotely, from a distance, or worse from below!
  • Cracking and collapsing of the snow are a red flag, indicating unstable snow conditions.
The sugary, faceted crystals in this widespread persistent weak layer just fall out of the pit wall in some places. People could trigger dangerous avalanches where a cohesive slab has formed on top of this buried layer.
These large faceted grains are more like the size and texture of rock salt than sugar. This is classic depth hoar, and it's likely to haunt us later in the season when slopes are overloaded by inevitable storms.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Strong and gusty west winds will whip up today's new snow at upper elevations and fresh drifts will form rapidly on lee slopes and in deposition areas. These drifts could be quite sensitive to human triggers and will overload slopes with poor snow structure. People could trigger fresh avalanches of wind drifted snow and up to 3-foot-thick hard slab avalanches on steep slopes, where drifts formed previously on slopes with buried persistent weak layers.
  • A small avalanche of fresh wind drifted snow overrunning a slope with poor snow structure could involve old snow and cause a much larger avalanche.
  • Watch for and avoid drifted snow at upper and mid elevations near ridge tops and in and around terrain features like gullies, cliff bands, and sub ridges.
  • Avalanches of previously wind drifted snow could be triggered remotely or from a distance.
  • Harder wind slabs may allow people to get out on them before releasing.
This is part of the crown of the Steep Hollow Avalanche from 1-8-2021. The avalanche involved previously wind drifted snow that failed on a deep persistent weak layer.
Additional Information
Check out our Blog featuring Paige and Greg discussing Danger Ratings and Persistent Weak Layers....HERE

Paige shows what we are talking about when we mention faceted snow in our forecasts. Watch the video HERE

This video shows what I found in Upper Providence Canyon last week...
General Announcements
Thanks to the generous support of our local resorts, Ski Utah, and Backcountry, discount lift tickets are now available. Support the UAC while you ski at the resorts this season. Tickets are available here.
Visit this website with information about Responsible Winter Recreation by the Utah Office of Outdoor Recreation.
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I will update this forecast by around 7:30 tomorrow morning.
This forecast is from the USDA Forest Service, which is solely responsible for its content. The forecast describes general avalanche conditions and local variations always occur.