BOTTOM LINE
Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)
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Danger Rose Tutorial
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There is a CONSIDERABLE danger in the backcountry today. The danger is greatest in exposed upper elevation terrain, and you could trigger dangerous wind slab avalanches on drifted slopes steeper than about 35 degrees. Periods of extremely heavy snowfall will cause an increasing danger of new snow avalanches, with spontaneous natural avalanches possible during short-lived windows of very high accumulation rates...Triggered and natural wet avalanches consisting of saturated fresh or rain soaked snow are probable on very steep slopes, and possible at all elevations...
Use conservative decision making, careful route finding, and continue to use good travel habits....Avalanche training and experience are essential. |
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CURRENT CONDITIONS |
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We're in the midst on a somewhat long duration springtime storm, with a wide open tap on copius tropical Pacific moisture. Looking like a productive water season, with the Cub and Logan River watersheds now holding average or a bit better than average water contents. The Tony Grove Snotel at 8400' reports 108% of average water for the date contained in 97 inches of total snow on the ground. About 5 inches of new snow accumulated at the station, with 7/10ths of an inch of water in the last 24 hours. The Ben Lomond Snotel, a bit to our south, reports around 5 inches of very heavy new snow containing 1.6 inches of water. The higher in elevation you go, the more snow and less slush you'll find.
The CSI weather station at 9700' reports strong and sustained winds overnight from the south-southeast. Currently reading 35 mph average wind speeds, with gusts to 65 earlier this morning. |
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RECENT ACTIVITY |
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Snow safety crews in the Wasatch Range yesterday reported numerous triggered fresh wind slab avalanches at upper elevations and wet sluffs lower down.
Locally: On Sunday, I triggered a couple wet sluffs in Cherry Canyon in the Mount Naomi Wilderness on a steep west-southwest facing slope at around 7500'. (4-12-09 PHOTOS). |
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THREAT #1 |
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PROBABILITY |
SIZE |
TREND |
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Over the next
24
hours.
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Strong and sustained south and southeast winds overnight created sizable wind slabs at upper elevations on lee slopes and in and around terrain features like gullies, cliff bands, and sub-ridges. These are likely to be sensitive to human triggers, and continuing snowfall and shifting winds today will continue to increase the danger, making potential wind slab avalanches larger and less manageable. |
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THREAT #2 |
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PROBABILITY |
SIZE |
TREND |
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Over the next
14 hours.
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Extremely heavy snowfall rates around the time of frontal passage (midday) will cause a rising danger and the potential for natural avalanches to spontaneously occur. Some of these could be fairly broad, and any avalanche has the potential to run far and fast on a steep sustained slope. You should stay out from under steep slopes and obvious or historic avalanche paths during periods of very heavy snowfall..... |
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THREAT #3 |
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| WHERE |
PROBABILITY |
SIZE |
TREND |
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Over the next
24
hours.
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Wet avalanches involving saturated new snow at upper mid elevations or rain-soaked snow lower down are probable on very steep slopes. Fresh snow quickly becomes sensitive this time of year with initial heating, and wet surface sluffs can entrain lots of heavy snow quickly. Any signs of warming will make me reevaluate today, and I'll likely decide to move off of and out from under steep slopes.
The danger of wet avalanches will continue to be a threat into the weekend, even after the moist storm departs the region... |
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MOUNTAIN WEATHER |
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The National Weather Sevice has continued a Winter Storm Warning through Friday morning for a broad area across the Inter-mountain West, the mountains around Cache Valley and Bear Lake are included in this. Substantial additional snowfall and continuing and shifting winds are possible and will likely cause an increasing avalanche danger today and tonight. The snowfall and storminess will cease on Friday..
High pressure and melt conditions will return for the weekend. |
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GENERAL ANNOUNCEMENTS |
Our "Know before You Go" video is available online..... (click HERE to watch it)
Please let us know what you're seeing in the backcountry, especially if you see or trigger an avalanche, by leaving us a message at (435-)755-3638 or 1-800-662-4140. Or, you can always e-mail us at uac@utahavalanchecenter.org. . Your observations are very important for our program.....
The Utah Avalanche Center depends on contributions from users like you to support our work.
I will be issuing intermittent and weekend advisories through the rest of April..... I will update this advisory by about 7:30 on Friday morning...
This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. |
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This information does not apply to developed ski areas or highways where avalanche control is normally done. This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. |
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This advisory provided by the USDA Forest Service, in partnership with:
The Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Division of Emergency Management, Salt Lake County, Salt Lake Unified Fire Authority and the friends of the La Sal Avalanche Center. See our Sponsors Page for a complete list. |
