Forecast for the Ogden Area Mountains

Mark Staples
Issued by Mark Staples for
Wednesday, February 20, 2019
With over a foot of new snow since yesterday morning and strong southerly winds at the highest ridgetops, human triggered avalanches are likely on any slope with wind drifted snow. The new snow may also produces very soft sluffs in the new snow even on non wind affected slopes. For these reasons the avalanche danger is CONSIDERABLE at upper elevations, MODERATE at mid and low elevations. Other parts of the Ogden area mountains received less snow and should have a lower danger but the danger today is based on places with the highest snow fall amounts.
Low
Moderate
Considerable
High
Extreme
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Special Announcements
An AVALANCHE WATCH has been issues for the La Sal and Abajo mountains in southern Utah where the avalanche danger is expected to rise to HIGH. Strong winds with periods of heavy snow will create widespread areas of unstable snow. The avalanche danger in these mountains will remain elevated through the weekend.
Other parts of southern Utah where we don't issue avalanche forecasts may have an elevated danger as well. We do post obs from the mountains of southwest Utah. View them here or submit obs here.
Weather and Snow
Yesterday 8 inches of snow fell near Snowbasin and another 8-9 inches fell overnight. This snow has more air than water in it. It is very low density (about 3%). Further east on the other side of the Ogden Valley about 6 inches fell since yesterday.
This morning temperatures are in the single digits F above 7000 feet. Winds increased since yesterday and are blowing 15 mph gusting 25-30 mph. At higher elevations near Ogden Peak, winds are averaging 30-35 mph and gusting 45 mph from the south-southwest.
Today snowfall will continue with another 6 inches by tomorrow morning, but who knows. If this situation continues, parts of the Ogden area mountains may receive more. Temperatures today will stay cold and should climb into the teens F. Winds may ease a little bit and shift a little more southerly.
Recent Avalanches
No avalanches were reported but yesterday afternoon the new snow was getting sensitive and loose dry sluffs were easy to trigger.
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
The new snow is very low density. Winds should easily drift this new snow and form soft slabs 1-2 feet deep that will easily fracture and produce avalanches today. Upper elevation winds were blowing strongly from SSW this morning. Gusty winds at lower elevations were even transporting a little snow. The best way to identify and avoid these drifts is to look for them. They look pillowy, rounded and smoother than freshly fallen snow. They are often found on the opposite sides of ridges or other terrain features from places where the snow is scoured.
Some faceting seems to have occurred in recent days within the top foot of snow. I found some of these weak facets about a foot deep yesterday near Salt Lake and Toby found some yesterday near Logan. I suspect there may be a similar layer in the Ogden area which could make any fresh slabs of wind drifted snow extra sensitive today and possibly fracture over wider than expected areas.
Avalanche Problem #2
New Snow
Type
Location
Likelihood
Size
Description
The new snow was falling at a rate of an inch per hour at times last night. This snow is incredibly light and probably hasn't had time to bond to itself. I doubt it will be slabby. It should produce easy sluffs on slopes without any wind effects.
Avalanche Problem #3
Cornice
Type
Location
Likelihood
Size
Description
With about 100 inches of snow falling in February and lots of strong winds, cornices have grown enormous. They will break back farther than you think, well back from the apex of the ridgeline. Exercise great caution along and underneath the heavily corniced ridgelines.
Additional Information
The accident reports for the four avalanche fatalities are all finalized with some first-hand accounts and worth reading. We all have something to learn so that we can get home safely to our loved ones. List of all accidents found HERE.
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.