Backcountry Avalanche Forecast for Aspen 	
Issued: 04/04/2011 6:51 AM by Brian McCall

Highlights

Skies will clear this morning after a stormy day on Sunday. 12-15 inches of new snow fell in many 
areas of the zone. Strong southwest winds blew at higher elevations, especially during the early 
part of the storm. Wind slabs will be your primary concern at higher elevations today. Watch for 
some triggered soft slabs below treeline as well.

Twitter 05/04/2011 5:17 AM by John Snook:  6th av-related fatality on Monday near Aspen. 

  04/04/2011 6:58 PM by Brian McCall:  5 people caught and 1 confirmed fatality in an avalanche in 
  the Aspen zone today. W side of Highlands Ridge.
  
Avalanche Danger

The avalanche danger for the Aspen zone is rated CONSIDERABLE (Level 3) for all slopes near and 
above treeline. Triggered avalanches are likely in lee and cross loaded areas at these higher 
elevations. Below treeline, the danger is MODERATE (Level 2) for all aspects. Triggered soft slab 
avalanches failing in the new storm snow layer are possible, especially in steeper terrain at the 
lower elevations.

Snow & Avalanche Discussion

A powerful spring snow storm moved through the area during the day time hours on Sunday. 12-15 inches 
of new snow fell by sunset in many areas of the Aspen zone. Strong southwest winds, and even some 
lightning, accompanied the early part of the storm. Winds remained strong above treeline for most of 
the day. Wind speeds did ease slightly at treeline after that initial strong start to the storm. 
Skies will clear this morning as the storm moves out of the state. A few afternoon clouds will form 
again as the day warm up.

Your first snowpack problem today will the wind slabs formed by strong southwest and west winds 
yesterday. The north through southeast aspects will have the deepest new slabs, especially above 
treeline. Keep an eye out for areas of cross loading on the other high elevation aspects and well. 
Winds are shifting towards the northwest this morning. They may be strong enough at times to 
transport more snow onto lee aspects above treeline today. Below treeline, watch for triggered soft 
slab avalanches today occurring in that new storm snow layer. These will be most problematic in 
steeper terrain. Colder overnight temperatures and a slow warm up today will have helped to freeze 
the wet snowpack we had below treeline yesterday. Wet avalanches will only be minor concern at the 
lowest elevations and on sunny aspects today.

Here comes the broken record part of our forecast. Deeply buried, persistent weak layers are still a 
problem throughout the state and in some areas of the Aspen zone. We continue to receive reports of 
isolated, large, triggered slab avalanches that are occurring. The most recent one happened on the 
Aspen side of Independence Pass on Saturday. It was triggered on a north facing slope at 11,500 ft. 
The crown was estimated to be 2-10 feet deep. It failed at the in the old snowpack running full 
track to the valley floor, about 2000 vertical feet below. Similar avalanches have been triggered 
on northwest to northeast aspects near or just above treeline throughout the state. These have 
usually occurred in areas with a shallow snowpack. In our region, the terrain around Ashcroft and 
Independence Pass is the most suspect for these large triggered avalanches due to shallow and weaker 
snowpack with more problematic facets in the lower snowpack.

Weather Discussion for 11,000ft 	Issued: 04/04/2011 1:16 PM by John Snook 	

Northwest flow keeps temperatures seasonably cool through Monday afternoon. Wind directions shift 
toward westerly Monday night allowing warmer air to return. Overnight temperatures will hold steady 
or even rise at ridgetop elevations. A flat ridge of high pressure on Tuesday brings mostly sunny 
skies over southern zones and partly cloudy skies to the north with milder temperatures. Strong 
gusty winds are likely east of the Continental Divide in the Front Range zone. Temperatures remain 
mild Tuesday night with only a minimal freeze at best. A weak cold front sags south into the state 
Wednesday afternoon bringing somewhat cooler temperatures late in the day. Mountain snow is possible 
Wednesday night into Thursday morning. A deep trough of low pressure builds over the Great Basin 
during the latter portion of the week putting Colorado in southwest flow. Periods of moisture and 
associated shower activity are possible. Unsettled weather arrives for the weekend as low pressure 
moves across the state.