Today the avalanche danger is HIGH on mid and upper elevation slopes. At lower elevations the danger is CONSIDERABLE. With continued snowfall and strong south winds, more avalanches are likely today. Most avalanches will occur in areas with wind drifted snow. Some may occur in the new snow on slopes not affected by the wind. Additionally some slides could break on buried persistent weak layers especially on slopes with a heavy load of wind drifted snow.
With more snow falling this morning and strong south winds blowing, any slope with wind drifted snow can produce slab avalanches today. Look for fresh wind drift and slabs on all slopes because gusty winds are occurring at all elevations. Signs of recent wind loading such as smooth, rounded, pillowly deposits of snow. Avoid these wind slabs and go to slopes sheltered from the wind.
Avalanches may also occur on slopes not affected by the wind. Pay attention to how the new snow reacts around your feet. It should easily produce loose snow avalanches and may also produce soft slab avalanches. These mostly likley will break on density changes within the new snow.
With yesterday's and today's new snow combined with wind loading, it may be enough for slab avalanches to break on layers of buried facets. Some facets formed this fall, others formed during recent cold weather. These persistent weak layers exist:
Some of the avalanches triggered on Saturday were an indication that some of these layers are still active. With today's loading, I wouldn't be surprised to see some avalanches breaking on these layers.
Where the snowpack is thin, all three layers can be combined. Yesterday at low elevations, Evelyn found sensitive faceted layers. They could be a problem in gullies and small steep slopes.
THE FOREST SERVICE UTAH AVALANCHE CENTER IN SALT LAKE CITY HAS CONTINUED A BACKCOUNTRY AVALANCHE WARNING.
* TIMING...THROUGH 6 AM MST TUESDAY.
* AFFECTED AREA...FOR THE MOUNTAINS OF NORTHERN UTAH INCLUDING THE WASATCH RANGE, BEAR RIVER RANGE, AND UINTA MOUNTAINS.
* AVALANCHE DANGER...HIGH.
* REASON/IMPACTS...VERY DANGEROUS AVALANCHE CONDITIONS EXIST. HEAVY SNOW COMBINED WITH WIND WILL CREATE WIDESPREAD AREAS OF UNSTABLE SNOW. BOTH HUMAN TRIGGERED AND NATURAL AVALANCHES ARE LIKELY. STAY OFF OF AND OUT FROM UNDERNEATH SLOPES STEEPER THAN 30 DEGREES.
Yesterday, early afternoon, many shallow soft slab avalanches in the new snow occurred during high snowfall rates. These were observed in ski areas and in the backcountry.
Photo below shows one of these avalanches triggered by a skier in Mill Creek Canyon (N. Grainger)
Yesterday's storm delivered:
More snow is falling this morning. As of 6 a.m. 4-6 inches of snow had fallen (0.3" to 0.4" of water) and temperatures are mostly in the upper teens F.
Strong ridgetop winds are blowing from the south at 30-40 mph with gusts of 60-70 mph. Even at lower elevations, winds are gusting to 25 mph.
Today strong south winds and snowfall should continue through the morning.
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.
