This is Chris Lundy of the Sawtooth National Forest Avalanche Center with your Backcountry Avalanche Advisory and Weather Forecast for Tuesday, January 29, 2008 at 7:30 am. The Wattis Dumke Foundation & the Friends of the Sawtooth Avalanche Center bring you this advisory. Special Announcement: We have DISCONTINUED the BACKCOUNTRY AVALANCHE WARNING for the mountains of South Central Idaho. This week is the 3rd Annual Avalanche Awareness Week. We will offer a 1 hr Avalanche Awareness Program tonight from 7-8pm at the Hailey Community Campus in Rm 301. The Best of Banff Film Festival and SNFAC Fundraiser is this Thursday, Friday, and Saturday at the NexStage Theater in Ketchum. Film Trailer: http://ca.youtube.com/watch?v=xeBYLLYnd_I&feature=related Film List: http://www.sawtoothavalanche.com/banff_film_list.doc Bottom Line: Today the avalanche danger remains HIGH in the South and Central Valleys. Yesterday a widespread avalanche cycle took place in this region, and I dont think any miracles took place overnight to cause the stability to be much better today. Yesterdays storm fell on a weak, faceted snowpack and it will take time for conditions to stabilize. I recommend avoiding travel on or beneath steep slopes. This certainly includes the out of bounds terrain on Baldy, but also roads and trails around the valley that pass beneath steep slopes. In the North Valley and Sawtooth Mountains the avalanche danger is estimated to be CONSIDERABLE. Buried facet layers exist in this region as well, but they are not as pronounced or widespread north of about the SNRA. However, I would still avoid traveling on any slope steeper than 30 degrees. There is enough wind in the forecast to continue the widespread wind loading that took place yesterday. The avalanche danger throughout our area will be the greatest on wind loaded slopes, but given the nature of yesterdays wind, every slope that didnt get scoured should be treated as wind loaded. Primary Avalanche Concern: Yesterdays snowfall was accompanied by very strong winds that loaded many slopes throughout our area, from upper elevation ridgelines to valley bottom sledding hills. The wind was responsible for numerous natural avalanches that occurred Sunday night, and when the wind shifted yesterday morning a whole new round of naturals took place. The avalanche danger throughout our region will be highest on wind loaded slopes, unfortunately this includes most slopes that arent scoured or thickly timbered. There is sufficient wind in the forecast to continue the widespread wind transport that took place yesterday, and this may produce natural avalanches today as slopes become overloaded. Secondary Avalanche Concern: Natural avalanches yesterday ran down to weak faceted snow buried about 2 feet deep, but also released on a density difference within the new snow. Increasing temperatures during the storm late Sunday resulted in a density inversion at the base of the storm snow. I would expect this to have settled out some overnight, but it will remain a concern today. In the South and Central Valley, especially at mid to lower elevations, the storm snow fell on top of a weak, faceted snowpack. At upper elevations, the facet layers are generally found about 2 feet deep and correspond to the snow surface that weakened during mid-January. At lower elevations the entire snowpack was weak and faceted, and many natural avalanches just off the valley floor ran to the ground. In our northern mountains beyond the SNRA, facet layers can also be found buried about 2 feet deep, but they are less developed and widespread. Very few backcountry sliders and riders were out yesterday so we have little information about this area. A skier reported widespread and large collapses in the flats below Durrance, but workers at Galena Lodge didnt receive any while packing snowshoe trails. I drove as far north as Owl Creek yesterday, but visibility was limited to lower elevations where there was much less avalanche activity than around town. Since we are dealing with a persistent weak layer in many areas, we can expect that the stability will take time to improve, and it certainly didnt happen overnight. I continue to recommend avoiding travel on or beneath steep slopes, especially in the South and Central Valley. I dont think its a good day to head OB on Baldy, and I wouldnt walk my dog on any local trails or roads with steep slopes above them. Many local walkers dont read the avalanche advisory so please pass the word. Avalanche Activity Summary: An impressive natural avalanche cycle took place on mid to low elevations slopes in the South and Central Valleys. Avalanches also took place at upper elevations but they were less widespread. Here is a brief and far from complete list of notable avalanches: - Della Mountain avalanched damming the Big Wood River and causing flooding. - Below the Warm Springs south slopes, several houses were hit and one slide crossed Sage Road. Most affected houses were avalanche built and little damage was reported. - Slopes above Highway 75 near Hulen Meadows and Lake Creek blocked the road early Monday morning. - The southeast aspect of Sun Peak avalanched several times between 9 and 10am, blocking Trail Creek Road. - Southeast facing slopes in Eagle Creek avalanched several times, hitting a home. - The slope behind Woodside Elementary School avalanched about 400 feet wide. Current Conditions: Yesterday morning, a few more inches of snow fell before the snowfall petered out with the passage of the cold front. With the front, temperatures plummeted and quickly reached the single digits to low teens. Strong winds continued, but shifted from the southwest to the west to northwest mid morning. This morning wind are increasing on Titus Ridge and currently averaging 20-30 mph from the west-northwest. Baldy has not seen this increase, with winds blowing 10-20 mph this morning. Temperatures at all elevations are currently in the low single digits. Mountain Weather Forecast: A minor storm system will move through our region later today, and we might get 2-4 inches of snow by tomorrow. Winds will remain strong in some locations, blowing 20-30 mph from the west shifting to the southwest. Temperatures will remain cold, with highs expected to reach 10-15 degrees in the mountains. A high of around 20 degrees is expected in the valley.