Forecast for the Ogden Area Mountains

Mark Staples
Issued by Mark Staples for
Wednesday, January 16, 2019
Today with new snow and some S and SW winds, the avalanche danger is MODERATE for triggering a shallow slab of wind-drifted snow at upper elevations. There could be a few isolated wind slabs at mid elevations but these are much less likely to exist. At mid and low elevations the danger is LOW where avalanche conditions are generally safe.
Avalanches breaking 1-2 feet deep on a persistent weak layer are unlikely today but remain a concern at mid and upper elevations especially with more snow coming that may start to awaken this layer.
Low
Moderate
Considerable
High
Extreme
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Special Announcements
Listen to the first full length episode of the UAC Podcast. Breaking the Stigma with Traumatic Stress - Another Conversation with Dave Richards. Download it on iTunes, Stitcher or from the UAC Blog.
Take time this winter to make avalanche education a priority for you and your backcountry partners. We will be offering "Backcountry 101 - Introduction to Avalanches" classes at Snowbasin on February 1-2 and Powder Mountain February 15-16. Get more details on the UAC Education page.
Weather and Snow
It's snowing this morning with about 2-4 inches of new snow.
Temperatures are mostly in the mid to upper 20's F.
Winds at ridgetops are blowing 10-15 mph with gusts of 25-35 mph from the SSW.
Today, temperatures should warm to near 30 degrees F. The strongest winds will be this morning and decrease some this afternoon. Snow should continue this morning but taper off by midday. Skies will stay cloudy and more snow returns tomorrow morning.
Recent Avalanches
No new avalanche activity has reported from the Ogden area mountains. If you're thinking of heading north, make sure to read the Logan area forecast, and all about their recent avalanches.
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
With new snow this morning and SSW winds, look for fresh slabs of wind-drifted snow. These can either be formed by wind-loading from the top of ridges OR cross loading along the edges of gullies and sub-ridges. The simplest way to deal with this problem is to look for it and then avoid it.
Ski cutting may be an option but it is a high risk maneuver that often surprises professional ski patrollers who have a lot of practice doing it. There are older wind slabs covered by new snow. These have most likely stabilized but a few could remain sensitive. Places with new wind slabs are likely places with older wind slabs.
Image below of top loading.
Image below of cross loading
Avalanche Problem #2
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
The various persistent weak layers of faceted snow in the Ogden area mountian snowpack are mostly dormant and are adjusting to the load of snow and wind from early last week. Many of these layers show up easily in a snowpit wall as a light grey stripe in the middle of the snowpack. Others may reveal themselves in tests like the Extended Column Test (how to video). In many mid and low elevations locations, recent very warm temperatures may have also helped heal these layers. The coming storm will be a good test of these layers. I expect they will reawaken as they get loaded, but we'll see in the next few days. The tricky part is that they may remain sensitive and produce avalanches through the coming weekend.
How have some of these persistent weak layers formed? Check out this new Blog by Greg Gagne that includes an explanation of near surface faceting. One persistent weak layer is called surface hoar which forms like frost on the snowpack. Below is a 3-D image by Doug Wewer of one of these crystals with small rime (like tiny droplets of freezing rain) on it.
Additional Information
The Wasatch range has a complex snow surface for the incoming storms to land on - near surface facets, surface hoar and a variety of weak crusts and hard old wind slabs with facets above and below. If you’re out and about today, see how the new snow has bonded to yesterdays snow surface.
General Announcements
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.