Forecast for the Salt Lake Area Mountains

Mark Staples
Issued by Mark Staples for
Wednesday, February 27, 2019
Today at upper elevations the avalanche danger is MODERATE where slabs of wind drifted snow can be triggered. The avalanche danger is LOW at mid elevations where avalanches of wind drifted snow are still possible. At low elevations the danger is LOW and wet avalanches of loose snow are possible.
Low
Moderate
Considerable
High
Extreme
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Special Announcements
Weather and Snow
Currently:
Temperatures are near 30 degrees F at 8000 feet and in the mid 20s F near 10,000 feet.
Strong southerly winds continued overnight and are blowing 15-20 mph gusting 30-40 mph this morning. At 11,000 feet gusts are reaching 60-80 mph.
These winds have damaged the riding quality on many slopes. Dry, soft powder can still be found on sheltered slopes above 9000 feet. At lower elevations the snow has become wet from warm temps.
For Today:
Strong southerly winds will continue and temps should warm into the low 40s F near 9000 feet. An inch or two of snow could fall today with a touch of rain below 7000 feet.
Photo below shows inverted ski tracks which is a sign of wind scouring the soft snow around those tracks.
Soft, dry powder is elusive but still exists on wind-sheltered slopes at mid to upper elevations. Photo below is at about 9500 feet on a NW facing slope.
Recent Avalanches
Yesterday a soft slab of wind drifted snow was triggered by a snowboarder in Martha Bowl on Pioneer Peak in the backcountry near Brighton (photo below). Similar slides were triggered by riders in lower Mineral Basin which is the backcountry terrain south of Snowbird. A few similar wind slabs were triggered on Monday as well. Most of these are breaking on a softer layer of broken snowflakes under the slab of wind drifted snow.
Also, some sluffs of wet snow were spotted in both north and south facing chutes in the middle and lower parts of Little Cottonwood Canyon
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
The main avalanche issues to watch out for are slabs of wind drifted snow. Winds don't have much snow left to transport, but they were still moving small amounts of snow yesterday. This avalanche problem can be tricky as some drifts and slabs stabilize while others remain unstable. Greg, Craig and I were in upper Little and Big Cottonwood Canyons yesterday. Many wind slabs appeared unreactive, but a snowboarder triggered one which is bull's eye information that some remain unstable.
These wind slabs are best to identify visually as they look smooth, rounded, pillowly, etc and typically exists adjacent to slopes that have been scoured. The photo below is a great example of scouring and with the arrow showing where you'd expect to find a fresh slab that could avalanche. Most of these wind slabs haven't been big enough to bury a person. They can cause trouble in other ways that would injury you. They should be mostly a concern at upper elevations. At mid and lower elevations, warm temperatures should help them stabilize.
Cornices are quite large, and continue to grow during this windy period. Avoid traveling underneath cornices, as well as anywhere near the edge of ridges as cornices may break back much further than expected. Although now a few days old, it is worth reading this excellent observation from Sunday (link) where the author cautions "Please, stay back from the edge! Even further than you think."
Avalanche Problem #2
Wet Snow
Type
Location
Likelihood
Size
Description
Watch for small sluffs of wet snow at low elevations. I don't expect this to be much of an issue but it is worth watching for. Only a drizzle of rain is expected, but if anymore than that falls there chance of wet snow avalanches occurring will go up quickly.
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.