Logan Avalanche Advisory

Forecaster: Toby Weed

BOTTOM LINE

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


Danger Rose Tutorial

There is a level 3 or Considerable danger in the backcountry today. Natural deep slab avalanches, wet avalanches, and cornice falls are possible during the height of midday solar warmth.. You could trigger large and dangerous deep slab avalanches, especially in isolated outlying areas and on very steep upper and mid elevation slopes with generally thin snow coverage... Deep slab avalanches could be huge, destructive, and quite likely will be unsurvivable. Wet avalanches will become increasingly likely with midday heat, and cornice falls could trigger dangerous avalanches on steep slopes below. Careful snowpack evaluation, cautious route finding, and conservative decision making will be essential today in the backcountry. Avoid steep rocky slopes with generally thin snow cover, slopes with warmth softened saturated snow, and overhanging ridge-top cornices. You'll find safer conditions in sheltered shady areas, and in lower angled terrain...


CURRENT CONDITIONS

It's already a toasty 32 degrees up at the 8400' Tony Grove Snotel this morning, and there's 82 inches of total snow containing 89% of normal water for the date. The 9700' Campbell Scientific Logan Peak weather station reports 30 degrees, and a west-northwest wind averaging only in the single digits this morning... Warmth and direct solar heating, with little cooling from very light winds, will cause a general increase in the avalanche danger today...


RECENT ACTIVITY

Two very experienced and well known local backcountry skiers were buried and killed in Grand Teton National Park near Jackson Wyoming. The avalanche, on the south side of Ranger Peak, probably occurred on Wednesday and the bodies were recovered by search and rescue teams yesterday... Click HERE for more details... For a story with a better ending: Sledders recovered a party member who was completely buried under several feet of heavy avalanche debris in the mountains near Kamas Utah on Sunday. For an excellent video recounting the miracle rescue, click... HERE

Locally; I checked out a recently triggered fresh deep slab avalanche in the Rodeo Grounds on the east side of Logan Peak yesterday afternoon.... I'm not exactly sure when this occurred, yesterday morning most likely, but possibly Wednesday afternoon. The hard slab avalanche on a southeast facing slope just above 9000' in elevation was 2 to 3 feet deep and around 50 feet wide, and it left a deep pile of debris in the flats at the bottom of the hill... For photos, link HERE.....

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


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 10 hours.

Depth hoar still plagues the basal layers of the snowpack in many areas, and you might trigger a dangerous deep slab avalanche, particularly in areas with generally shallow and weak snow... It is possible that a cornice fall, or a smaller avalanche overrunning a slope with poor snow structure could cause a much larger and more dangerous deep slab avalanche. Avoid shallow or rocky terrain at upper and mid elevations, and keep in mind that you are most likely to trigger a very dangerous deep slab avalanche from an area where the slab layer is relatively thin. There are also a couple other buried persistent weak layers to be concerned with, consisting of notoriously persistent feathery frost crystals or surface hoar and small sugary grains called near surface facets. Today's solar warming will increase the creep rate of the slab layer and gravity will pull it down along existing weak layers. Also the warmth will soften the hard slabs, making them easier for you to trigger. Deep slab avalanches 2 to 4 feet deep may be quite easy to initiate in some areas, and you might trigger one remotely, from a distance, or worse from below.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 10 hours.

Wet sluffs and slabs will become more likely during the heat of midday, and you should get off and avoid steep slopes with warmth softened saturated snow.


THREAT #3

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Cornices will sag with today's heating and some may naturally calve-off. It's quite possible that a cornice fall could trigger a dangerous hard slab avalanche on a steep slope below...


MOUNTAIN WEATHER

It will be warm and sunny today, with mostly calm winds. 8500' high temperatures will climb well into the 40s, and very light west-northwest winds will likely fail to cool things off.... Temperatures should drop into the mid twenties overnight and west winds will continue to be on the light side. Above average temperatures will persist through the weekend. The next round of unsettled weather will affect the Logan Zone early next week, with a chance of snow on around Tuesday....


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.