Wasatch-Cache National Forest:  In partnership with:  Utah State Parks and Recreation, Friends of the Utah Avalanche Center-Logan, and Utah State University College of Natural Resources.

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Logan area Avalanche Advisory

7:30, Monday February 4, 2008

Hello and good morning, this is Toby Weed of the Utah Avalanche Center with your Logan Area backcountry avalanche and mountain weather advisory.  It’s Monday February 4th, at 7:30 in the morning. This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from the Trailhead.

Current Conditions:

Snow keeps falling in Logan, and the white stuff will likely continue to fall through much of the day in the mountains. Yesterday’s storm was quite productive, and the total snow reading at the Tony Grove Snotel climbed above one hundred inches for the first time this season, now recording 104+” with 98% of average water content. The total snow stake picked up 14 inches with 1.1 inches of water in the last 24 hrs. Seems like a lot, but not when compared to the Ben Lomond Peak Snotel’s amazing reading of 4”of water since yesterday morning. As the snow fell heavily yesterday, southwest winds gradually diminished while swinging around from the west. Its 5 degrees at the Campbell Scientific weather station at 9400’ on Logan Peak and northerly winds are averaging less than 10 mph.

Avalanche Conditions:

Most people wisely stayed out of backcountry avalanche terrain yesterday and so there were no reports of avalanches in the mountains around Logan. Ski areas and road crews in the Wasatch Range report a very active control day, with long running and sensitive soft slabs in the 2’+deep range triggered by both ski cuts and explosives. We received numerous reports of avalanche encounters from Saturday, with several triggered avalanches, some stepping into old snow and a handful of people taking unintended rides.

I have reports of a couple spooky human triggered avalanches from this weekend in the Logan Area, and we’ve observed evidence of numerous natural wind slab avalanches in the backcountry over the last week. I’ve posted pictures of a few of these on the images page. The reports and observations are mainly from lower and middle elevations, and there have been recent local avalanches on a wide variety of slopes facing most directions and at all elevations. I’ll quickly sum things up. We’ve been getting a powerful Pacific storm regularly every two days for the last week. Strong winds before and during the storms have been building huge cornices, and extensive drifting formed widespread hard and soft slabs on steep slopes and avalanche paths in the region. We noted spotty natural wind slab avalanches early last week, and much more widespread and larger avalanches occurred in several areas on Thursday night, (see backcountry avalanche list). Skiers triggered a couple dangerous avalanches over the weekend; on Friday in the foothills south of Green Canyon, and on Saturday in the Garden City/Swan Peak gut.

You are most likely to see fresh soft slabs or sizable sluffs on steep slopes in the new snow today. The most dangerous will be fresh drifts and broad soft slabs consisting of new snow that are likely be sensitive to your presence and could run far and fast. Triggered soft slabs in the 1 to 2 foot deep range are likely today, and we could also see some sizable natural activity in some areas.

Wind-drifted snow overloaded some steep slopes with existing persistent weak layers, and there is potential for some avalanches to step down to one of several lingering weaknesses formed on the snow surface before last week.  In areas with a shallow overall snowpack, like many slopes in Blacksmith Fork, some avalanches could step all the way down to sugary depth hoar near the ground.

Bottom Line:

Overall, there’s a CONSIDERABLE danger in the backcountry today, and triggered avalanches are likely on a variety of steep slopes and at all elevations. In areas that received the most snow and on slopes exposed to wind drifting there is a lingering HIGH danger, and some natural avalanches are likely. In some areas, wind-drifted snow overloaded slopes with existing persistent weak layers, and the danger could remain CONSIDERABLE for a while.

Mountain Weather: The National Weather Service has continued a Winter Storm Warning for the mountains around Logan through this evening. Expect several additional inches of accumulation and moderate northwest winds today. The next Pacific storm will affect mainly Northern Utah tomorrow night into Wednesday. Another storm will glance by on around Thursday, and ridging or a break in the storms is expected for next weekend.

General Announcements: This advisory will expire in 24 hours from the posting time.

Go to the Avalanche Encyclopedia if you have any questions about terms I use in the advisory.

I'm very interested to know what you're seeing out there.  Please e-mail observations to me at [email protected] or leave me a message at 755-3638, especially if you see or trigger an avalanche in the backcountry. We keep all observations confidential.

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.