Backcountry Avalanche Forecast for Aspen 	
Issued: 01/18/2012 7:05 AM by Brian McCall

Highlights

Dangerous avalanche conditions still exists in the backcountry of the Aspen zone today. Monday's 
storm brought 9-16+ inches of new snow to the forecast area. Moderate to strong southwest winds 
blew during the storm. Winds speeds increased even further out of the southwest on Tuesday. The 
new snow and wind slabs have fallen on top of a very weak old snowpack. Backcountry travelers will 
be able to trigger avalanches on many steep slopes today,  including slopes below treeline. 
Travelers may trigger these avalanches remotely, and in some cases, from a long distance away. 
Thorough terrain evaluation, cautious route finding, and conservative decision making are essential 
for safe backcountry travel.

Avalanche Danger

The avalanche danger for the Aspen zone is CONSIDERABLE (Level 3) for slopes facing northwest, 
north, northeast, east, southeast, south and near and above treeline. In wind loaded areas, 
triggered and natural avalanches have potential to be large and destructive. The danger is 
MODERATE (Level 2) on west and southwest aspects at these higher elevations. Below treeline, 
you will find CONSIDERABLE (Level 3) danger on slopes facing west, through north, through 
southeast, and MODERATE (Level 2) danger on the south and southwest aspects.

Snow & Avalanche Discussion

Storm totals from Monday varied between 9 and 16 inches throughout the Aspen zone. The deepest 
storm totals fell in the southwest portion of the forecast area around Marble and Schofield Pass. 
Winds during this storm were moderate to strong out of the southwest. Wind transport increased on 
Tuesday under the influence of more strong southwest winds at higher elevations. Strong winds and 
more snow in the forecast for later this week will keep avalanche danger elevated for some time.

Numerous soft slab avalanche have been observed than ran during the last two days as a result of 
the new snow and wind. The highest number of avalanches occurred near and just below treeline on 
slopes facing north, northeast and east, although reports did come in with avalanches from all 
elevations and many aspects. Significant wind loading has occurred on easterly aspects near and 
above treeline, and many of these loaded slopes are capable of producing large avalanches today. 
They are just waiting for a trigger. That triggered could come in the form of more wind loading 
and light snow, or backcountry travelers near steep slopes in the backcountry. In all areas of the 
zone, our shallow old snowpack contains many weak layers. These weak layers have been severely 
stressed by the weight of new snow and wind slabs. Observers have noted shooting cracks that run 
down through the full depth of the snowpack. Some of these collapses and shooting cracks will lead 
to remotely triggered avalanches.

It has been a dry winter so far, but you will want to keep that powder fever in check this week as 
the potential for both natural and triggered avalanches, some of which may be large and destructive, 
exists on many steep slopes. Careful route finding and terrain selection will be mandatory for safe 
backcountry travel. Be aware of steep slopes near or above your group. In these conditions, 
avalanches may be triggered from flatter terrain below or off to the sides of steep avalanche paths.

Weather Discussion for 11,000ft 	Issued: 01/18/2012 1:02 PM by John Snook 	

West-northwest flow Wednesday night generates very strong alpine winds favoring northern and 
central zones. Speeds are strongest east of the Continental Divide in the Front Range and Sawatch 
zones. Snow develops overnight, but the forecast models are showing mixed signals with amounts, 
which are trending downward compared to earlier runs. The two favored areas are the Park Range 
with 8-12" and the Indian Peaks/Rocky Mountain National Park area with 4-8" by Thursday morning. 
Generally 1-3" expected for other northern and central zones and nothing to the south. Temperatures 
hold steady overnight. Wind directions shift to westerly on Friday as speeds trend downward, but 
remain strong in the usual Vail-Summit and Front Range locations. Moderate snow persists in the 
Steamboat zone with another 3-5" possible, while periods of light snow continue with light 
accumulations across other northern and central zones. Similar conditions continue through Friday 
with snowfall favoring the Steamboat zone and moderate to strong alpine winds from the west. Friday 
night brings a brief respite followed by another round of mountain snow for the weekend.

Weather Forecast
Fields 				Wednesday Night 	Thursday 		Thursday Night
Temperature (°F) 	10 to 15 			22 to 27 		12 to 17
Wind Speed (mph) 	20-30 G45 			15 to 25 		15 to 25
Wind Direction 		W 					W 				W
Sky Cover 			Overcast OV 		Mostly CloudyMC ->
Snow (in) 			1 to 3 				0 to 1 			0 to 2