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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Overall, the danger in the Logan Area Backcountry is CONSIDERABLE (3) this weekend, and dangerous avalanche conditions exist on many steep drifted slopes. This morning, there is a HIGH (4) danger on drifted upper elevation slopes with buried persistent weak layers steeper than about 35 degrees. Both natural and triggered wind slab or more dangerous deeper persistent slab avalanches are likely on northwest through east facing slopes. Although the danger will diminish somewhat with the departure of this morning's storm, dangerous avalanche conditions are likely to persist through the weekend. Most likely not a problem until tomorrow, but wet avalanches will become possible with daytime warming on any steep slope with saturated snow.
You should avoid travel on or under steep slopes and obvious or historic avalanche paths in drifted upper elevation terrain. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential for safe backcountry travel this weekend. |
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CURRENT CONDITIONS |
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Heavy snowfall and strong winds overloaded slopes with buried persistent weak layers in drifted upper elevation terrain, and dangerous avalanche conditions exist in the backcountry... But, you can also find good powder conditions and there are plenty of untracked sheltered lower elevation and lower angled slopes where you can find generally stable snow and much safer conditions. The Tony Grove Snotel reports a storm total about 10" of new snow containing 1 inch of water in the last 6 hrs. The station reports 80" of total snow with 67% of average water for the date. Its 14 degrees up at the CSI Logan Peak weather station at 9700'. After averaging in the mid 30s and gusting to 60 mph from the southwest overnight, the wind shifted early this morning and is now coming out of the northwest... |
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RECENT ACTIVITY |
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Last Saturday a rider on a powder-surf board triggered a soft wind slab avalanche (12-18" deep and 50' wide) and was then caught and carried over rocks in steep terrain west of Tony Grove Lake. (3-27-10).
Separate parties of skiers each remote triggered large and destructive hard slab avalanches on the south side of Providence Canyon on Thursday (4-1-10)... Both avalanches, on generally north facing drifted slopes at around 9000' in elevation, involved several layers of very hard old snow and failed on persistent weak layers consisting of sugary, faceted snow... Here's an updated local backcountry avalanche list:
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THREAT #1 |
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PROBABILITY |
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TREND |
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Over the next
24 hours.
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The two large triggered persistent slab avalanches up in Providence Canyon on Thursday (4-1-10) and continued observed collapsing in some areas prove that this problem is still real in our region..... Slopes with weak (and generally shallow) snow structure can be found in many areas.... On slopes with significant recent deposits of wind drifted snow, slabs overloading layers of sugary weak snow have apparently become heavy and hard enough to fail.... Last night's additional loading from snow and especially wind drifting is likely to overload the weak snow on more slopes...
In these conditions, you might trigger a deep or persistent slab avalanche from a distance, or worse, from below.... |
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THREAT #2 |
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PROBABILITY |
SIZE |
TREND |
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Over the next
24 hours.
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Watch out for fresh or buried wind slabs near ridge tops, around rock outcroppings or cliffy areas, near sub-ridges and in gullies or scoops. Today's wind slabs will not necessarily be obvious and you should use caution in complex terrain... Even shallow or soft wind slabs or storm snow avalanches could be a problem if you get caught and carried into trees or other terrain traps below....
Storm snow and wind slab avalanches are possible this morning and the danger is likely to rise tonight, with significantly more snow and intensifying southwest winds likely. Storm snow avalanches may fail on weak layers or density differences within the new snow. Natural avalanches involving the new snow probably will occur tonight during periods of intense heavy snowfall or with sustained wind drifting... |
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THREAT #3 |
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PROBABILITY |
SIZE |
TREND |
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Over the next
36 hours.
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The saturated snow at lower and mid elevations was insulated by the new snow and it's still soft and punchy on some steep slopes... Wet avalanches are possible in these areas even when the air temperature is cool.... When the sun comes back out, solar or seasonal warming may cause a rapid increase in the danger of loose wet avalanches involving the fresh snow... Point release avalanches may entrain significant quantities of moist surface snow, and could gouge into older snow.... |
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MOUNTAIN WEATHER |
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The National Weather Service has continued a Winter Storm Warning for the mountains of Northern Utah for through noon. Snow showers will continue in the mountains today and temperatures should stay fairly cool... A strong northwest wind will gradually diminish to the moderate range this afternoon. 2 to 4 inches of additional accumulation is expected. More snow is expected this weekend with a fairly strong looking storm expected Sunday night through Tuesday..... |
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GENERAL ANNOUNCEMENTS |
Send us your avalanche and snow observations. You can call the SLC office at 800-662-4140, or email to uac@utahavalanchecenter.org
Donate to your favorite non-profit – The Friends of the Utah Avalanche Center. The UAC depends on contributions from users like you to support our work.
The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.
With limited funding available, we'll go to weekend and intermittent updates in April. Thanks for checking in.... |
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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. |
