Wasatch Cache and Uinta National Forests

In partnership with: Forest Service Utah Avalanche Center, The Friends of the Utah Avalanche Center and Utah State Parks.

Avalanche advisory

Saturday, March 29, 2003

Good Morning. This is Craig Gordon with the Forest Service Utah Avalanche Center with your avalanche and mountain weather advisory for the western Uinta Mountains including but not limited to the terrain surrounding Chalk Creek, Smith-Moorehouse, the Mirror Lake Highway, and Woodland. Recent fieldwork conducted on the Evanston side of the range and near Daniels, indicates similar snowpack conditions.

This advisory is made possible through a generous grant provided by Utah State Parks and will be available for the rest of the winter on weekends and holidays.

Today is Saturday, March 29, 2003, and it’s 7:30 in the morning.

Current Conditions:

Under clear skies, temperatures are starting to creep out of the single digits and it’s in the low teens at most mountaintop locations. Winds are generally out of the northwest at speeds of 10-20 mph along the ridges. The mid week storm event was good to us as we received 18”-21” of new snow in the high country. While there is some wind damage in the more exposed upper elevation terrain, riding and turning conditions remain quite good on sheltered, shady slopes. Today would be the day to get after it as a strong warming trend is forecast for Sunday and Monday.

Avalanche Conditions:

March madness continues in the Uintas and our mid week storm proved to be a pretty wild system. As the cold front pushed through the region on Wednesday night, winds raged out of the west, northwest, and north. At the most exposed ridgeline locations, wind speed averages were in the 50’s and 60’s for several hours and gusts were near 90 mph. These strong sustained winds moved a lot of snow around forming dangerous, cohesive hard slabs, on the leeward side of upper elevation terrain. Normally slabs are fairly easy to detect because of their rounded appearance and chalky texture. However as this storm system exited the region, winds calmed down and about 6” of snow fell out of the sky without any wind. This last gasp of snow helped to hide the slab underneath it, making it harder to detect. While these are great conditions for riding and skiing, because the snow feels solid underneath us, remember that hard slabs provide a false sense of security and often lure us well out onto the slope before they fail. Once triggered avalanches will have the possibility today of breaking into deeper, buried weak layers. A large natural avalanche that occurred on the east face of Bald Mountain fits this bill. This slide initiated within the new snow, but quickly stepped down into weaker snow near the ground. The crown of this avalanche was close to 6’ in depth. A large, nasty hard slab such as this still tells me our deep instabilities aren’t going away and steep, rocky terrain continues to be suspect. Though a number of slide paths have run naturally, those that haven’t are just waiting for the right trigger to come along and tip the balance.

With such strong sustained winds, loading would have occurred in some unusual places. I’d be suspicious around terrain features such as chutes, gullies, and sub-ridges where slabs could have formed.

While much of the wind activity occurred at the highest elevations throughout the region, I’d suspect that slabs would have formed on the leeward side of mid elevation ridges too.

In addition to winter type avalanche conditions today we’ll also need to think about wet, spring like avalanches as well. Remember that the sun is strong and its warming effects can be felt on all aspects. As the day wears on you’ll want to get off of and out from underneath steep sun exposed aspects.

Bottom Line:

Above timberline the avalanche danger is CONSIDERABLE today on any steep slope with recent deposits of wind drifted snow. Human triggered avalanches are probable in this type of terrain.

At mid elevations there is a MODERATE avalanche danger on steep wind loaded slopes, especially along the leeward side of exposed ridgelines. Human triggered avalanches are possible.

Out of wind-affected terrain and on slopes less steep than about 35 degrees the avalanche danger is generally LOW.

The danger of wet avalanches is LOW this morning, but will increase to MODERATE on steep sun exposed slopes as the day progresses.

Mountain Weather:

A beautiful day is on tap as high pressure dominates the weather pattern for the next couple of days. Skies will be clear and high temperatures at 10,000’ will be in the mid 20’s and at 8,000’ near 32 degrees. Overnight lows will be in the mid teens. Winds will be out of the west and northwest at speeds of 10-20 mph along the ridges. Sunday looks to be another nice day with slightly warmer temperatures and partly cloudy skies. On Monday we should see much warmer temperatures with a decent shot of snow developing by midweek. For the extended outlook, if we believe the computer models winter will return in earnest next weekend. I’ll keep you updated as things develop.

General Information:

If you’re getting out and about please let us know what you’re seeing, especially if you see or trigger an avalanche. Call 1-800-662-4140, or 801-231-2170, or email to [email protected] or fax to 801-524-6301. Your observations could help to save someone’s life. I’ve received some great observations this past week and thanks to those of you who called in with timely snowpack and avalanche information. Please keep them coming!

We will be offering free snowmobile specific avalanche education this year. To schedule a talk and or a field day please call 801-231-2170.

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.

I will update this advisory by 7:30 a.m. on Sunday, March 30, 2003.

Thanks for calling!