Logan Avalanche Advisory

Forecaster: Toby Weed

AVALANCHE WARNING »

Dangerous avalanche conditions are occuring or are imminent. Backcountry travel in avalanche terrain is not recommended.
Notice:

An avalanche warning continues for the mountains in the Logan Area. Very strong winds at all elevations combined with dense snow created a HIGH avalanche danger on many slopes. Avalanches may occur in unusual areas. Especially avoid any steep slope with recent wind deposits.


BOTTOM LINE

Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)


Danger Rose Tutorial

Heavy snow and very strong and sustained west winds created dangerous avalanche conditions in the Logan Zone. There's a level 4 or High avalanche danger in drifted terrain at upper and mid elevations in the backcountry. Natural and human triggered wind slab, persistent slab, and deep slab avalanches remain likely again today. Ridge-top cornices could still be quite sensitive. They may break further back than you expect, and could trigger dangerous avalanches on drifted slopes below. Avoid and stay out from under steep drifted slopes and obvious or historic avalanche paths in the backcountry.


CURRENT CONDITIONS

Sustained and very strong west winds, and significant heavy moist snow accumulation have created dangerous avalanche conditions on steep slopes in the backcountry today.... Temperatures dropped in the mountains overnight and it's16 degrees up at the 8400' Tony Grove Snotel this morning. There is now 80 inches of total snow on the ground containing 86% of normal water for the date. The site reports about 10 inches of snow from Tuesday and a few more last night, containing close to three inches of water equivalent... The CSI Logan Peak weather station at 9700' reports 7 degrees this morning, and the wind sensor is rimed. Very strong and sustained westerly winds continued all day yesterday and cranked out hourly average windspeeds exceeding 50 mph with gusts in the mid 60s overnight as recorded at the Hwy 89 Logan Summit weather station....


RECENT ACTIVITY

A rider triggered and was caught and carried by a 3' deep and 200' wide avalanche yesterday in Crescent lake Canyon out of Franklin Basin. Luckily, he was able to stay on his sled and ride out of the flowing debris before it ran through some large trees, leaving snow plastered over 12 feet up the thick trunks...

A rider triggered and was caught by a 3 foot+ deep slab Monday morning in the Beaver Creek Area just north of the Idaho State Line. He quickly grabbed a small aspen tree and watched as the 60' wide hard slab swept his sled several hundred feet through the trees below inflicting a fair amount of damage to the machine. Click HERE for more details and some great Go-Pro footage of the action... Very weak faceted snow or depth hoar still plagues many slopes in the area, and dangerous hard slab avalanches are obviously still quite possible in some areas.

(go to our current conditions page for more details on local activity and reports of other recent avalanches in Utah)


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Very strong and sustained westerly winds created high danger of wind slabs in upper and mid elevation terrain exposed to drifting. Natural wind slab avalanches are still probable today, and many occurred yesterday and overnight. Triggered wind slab avalanches are very likely today on steep slopes in drifted terrain. Wind slabs formed on the lee sides of major ridge lines and in and around terrain features like sub-ridges, gullies, scoops, and cliff bands. Fresh wind slabs in exposed upper elevation terrain could be in the 2 to 4+ foot deep range. Ridge-top cornices are likely to be sensitive and tricky, and they are likely to break further back than you expect. Cornice falls are likely to trigger avalanches on steep drifted slopes below...


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Wind slabs and storm snow piled up on top of shallowly buried suspect weak snow that was on the surface in early February. A couple layers of feathery surface hoar crystals and widespread small sugary near surface facet grains were well preserved by the light snowfalls in the last week or so. These have become active with recent significant loading. Soft slab avalanches failing on buried persistent weak layers are likely to be 2 to 3 feet deep, and will fall into the unmanageable category..... Today, persistent slab avalanches are likely to be quite sensitive, and you might trigger one remotely, from a distance, or below. Pay attention to red flags like whumpfing and shooting cracks, and avoid slopes steeper than about 30 degrees... Avalanches failing on buried surface hoar tend to fool people by releasing on lower angled slopes than expected....


THREAT #3

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

It is possible that a wind slab, a persistent slab avalanche, or a cornice fall overrunning a slope with poor snow structure could cause a much larger and more dangerous deep slab avalanche... You also could trigger a dangerous hard slab avalanche on a steep slope facing the northern half of the compass, particularly in areas with shallow and weak snow... Avoid shallow or rocky terrain at upper and mid elevations, and keep in mind that you are most likely to trigger a very dangerous hard slab avalanche from an area where the slab layer is relatively thin. It is possible the weight of a single person could be enough to trigger a large avalanche, and you might trigger one remotely, from a distance or below.


MOUNTAIN WEATHER

Temperatures dropped significantly and winds diminished substantially early this morning in the mountains... It'll be mostly cloudy today, with moderate northwest winds and 8500' high temperatures around 20 degrees. Tonight northwest winds will calm and we're expecting low temperatures of around 10 degrees. It'll be mostly sunny tomorrow with warmer temperatures and a moderate west wind.... The next energetic pacific storm will bring more snow to the zone for the coming weekend, with another foot or so of accumulation possible....


GENERAL ANNOUNCEMENTS

Please consider a donation to your favorite non-profit –The Friends of the Utah Avalanche Center. The Utah Avalanche Center depends on contributions from users like you to support our work.....

Please send us your observations from the backcountry especially if you see or trigger an avalanche, but also even if you don't.. go to avalanche and snow observations. You can also call me directly at 435-757-7578 or leave us a message at our office, 801-524-5304.... And, you can always send us a simple email by clicking HERE

I will update this advisory by around 7:30 in the morning on Mondays, Wednesdays, Fridays, and Saturdays.....

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.


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.


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.