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:

We are issuing an avalanche warning for the backcountry in the Logan Area. Heavy snow, strong and sustained west winds, and warming temperatures are creating dangerous avalanche conditions and a High avalanche danger at upper elevations. Natural and human triggered avalanches are likely today. Avoid and stay out from under steep drifted slopes and obvious or historic avalanche paths.....


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, strong and sustained west winds, and warming temperatures are creating 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 are all likely today. Ridge-top cornices will be quite sensitive and may break further back than you expect and could trigger 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 still intensifying west winds, warming temperatures, and heavy moist snow accumulation have created dangerous avalanche conditions at upper elevations in the backcountry today.... It's a balmy 31 degrees up at the 8400' Tony Grove Snotel this morning, and there is now 79 inches of total snow on the ground containing 85% of normal water for the date. The site reports about 10 inches of snow from yesterday, containing a bit over two inches of water equivalent... The CSI Logan Peak weather station at 9700' reports 25 degrees this morning, and the wind sensor became rimed overnight while recording sustained west winds.. The westerlies continue to gradually crank it up, with 40 mph average wind speeds and gusts in the mid 60s recorded overnight at the Hwy 89 Logan Summit.


RECENT ACTIVITY

Ogden Area resorts report active avalanche conditions with control work yesterday, and reports from the Wasatch backcountry include numerous small easily triggered avalanches.

Locally: 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.

Also. riders intentionally triggered a few wind slab avalanches in the Tony Grove Area on Monday in exposed upper elevation terrain, up to around a foot deep. We stayed in mostly low angled terrain yesterday and triggered some shooting cracks up to around 35' long on a mildly drifted slope in upper Bunch Grass...

(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.

Continuing strong and sustained westerly winds created a still rising danger of wind slabs in upper and mid elevation terrain exposed to drifting. Natural and triggered wind slab avalanches are likely today, and will be easily triggered by cornice falls or people. Wind slabs will continue forming 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 quite sensitive and may break further back than you expect.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Wind slabs and storm snow are piling 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. It's likely that these will become active with recent significant loading. Soft slab avalanches failing on buried persistent weak layers are likely to be 1 to 3 feet deep, and could well fall into the unmanageable category.


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

. Expect continuing sustained and gusty west winds at upper elevations and gradually rising temperatures today, with a high of 36 degrees forecast for 8500', and snow changing over to rain below around 7000'. Snow is again likely in the mountains tonight, with 2 to 4 inches of accumulation forecast.. West northwest winds will reach their peak, with gusts in the 70 mph range likely. Temperatures will drop significantly with a frontal passage overnight into the lower teens.... Light snowfall should continue tomorrow, with a moderate northwest wind, high temperatures around 20 degrees and a couple inches of accumulation possible.... Expect a bit of a break on Friday and a potent Pacific storm over the weekend.


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.