Today, the avalanche danger is MODERATE across all upper-elevation steep terrain for triggering shallow soft slabs of Wind-Drifted Snow. We also have a MODERATE avalanche danger across all mid and upper-elevation terrain for New Snow avalanches. Here, loose-dry and shallow soft slab avalanches failing within the new storm snow are possible. The wild card is the strong April sunshine. See the Wet Snow description below.
For the past 24 hours, the west-northwest wind has been blowing at perfect loading speeds of 10-25 mph. Because of this, you can expect shallow soft slabs of wind-drifted snow across the upper elevation ridgelines and on lee slopes. Be on the lookout for snow that looks pillowy, rounded, or wavy, and avoid those areas, as they are likely wind slabs.
Loose-dry avalanches (sluffs) will be easily initiated in steep terrain. With all the slick and hard underlying surfaces I would expect loose-dry avalanches to run fast and far and could pack a punch.
You will also want to be on guard for shallow soft slab avalanches failing on or at the old snow surface or within the new storm snow itself (density changes). Soft slabs of new snow are usually more sensitive during high precipitation periods which is now over. Therefore you need to determine how the new snow is settling and bonding.
Trend: Decreasing Danger
I am not adding a danger rating for this problem since it will depend completely on cloud cover and sunshine. The mountain temperatures are forecast to be cold with cloud cover and wind, so I have no clue if the sun will come out or if the new snow will be affected by warming.
It's April, and the sun is strong. All it takes is a few minutes of strong sunshine to warm the cold snow and instantly turn it wet and unstable. We can go from LOW danger to HIGH danger in a matter of minutes. Wet-loose avalanches in long steep sustained terrain can become very large and dangerous, especially with a very hard bed surface for them to run on. This time of year Wet Snow should be in the back of your mind every day.
Yesterday seemed oddly quiet, with very few observations coming through. In the Wasatch one avalanche was reported from Day's Fork in Crystal Palace. It was 9" deep x 150' wide, and they reported it to be surprising how fast and far it ran. Ski areas reported sensitive soft slab avalanches failing within the new snow on density changes.
Do We Let Our Guard Down in the Spring? --- UAC Avalanche Education coordinator McKinley Talty looked at the numbers....and his blog just might surprise you.
Under partly cloudy skies the mountain temperatures remain cold and range from 15-20 °F. The wind has calmed down in the past few hours and now blows from at speeds of 5-10 mph.
The upper Cottonwoods were in the hot spot stacking up the high-end of the storm totals, while other areas lower in the canyons or along the Park City Ridgeline came in closer to 8-17 inches. Provo was left holding the bag.
Today, we should see partly to mostly cloudy skies. One weather model showed snowfall until 2:00 PM, while another showed no chance of snow. Hopefully the first one is correct and we see light snowfall throughout the morning hours. In either case we are likely to only see a trace to a couple of inches at best. Temperatures will climb into the upper 20s to low 30s °F. Winds will remain from the west-northwest and blow 10-25 mph with gusts into the 20s and 30s.
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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.
