Backcountry Avalanche Forecast for Aspen Issued: 02/22/2011 6:53 AM by Brian McCall Highlights Only a few light snow showers fell in the last 24 hours. Very little new snow accumulation is showing up on local weather stations. Winds speeds have eased and shifted towards the southwest this morning, though they remain gusty at higher elevations. Avalanche danger will continue to ease as well, though potential still exists for large triggered avalanches on wind loaded, higher elevation slopes. Persistent weak layers are also still buried in the snowpack near and below treeline on shady aspects. Colorado's 4th avalanche fatality of the season occurred on Sunday in the Routt National Forest near Sand Mountain, northeast of Meeker. A snowmobiler was caught and killed in an avalanche on a lower elevation north facing slope (image below). Preliminary information can be found here. Avalanche Danger The avalanche danger for the Aspen zone is rated CONSIDERABLE (Level 3) on slopes facing northwest through east near and above treeline. Strong winds with the last storm loaded these aspects with slabs and large triggered avalanches can still occur. Continue to use caution on these slopes. On the windward aspects near and above treeline and all slopes below treeline the danger is MODERATE (Level 2) today. Triggered avalanches are still possible and they could be large in isolated areas. Watch for areas of cross loading on those higher elevation windward aspects and old persistent weak layers below treeline. Snow & Avalanche Discussion Strong winds and new snow dominated our weather over the weekend. Storm totals varied from 8-20 inches around the Aspen zone. Winds blew out of the south and southwest early in the storm and shifted towards the west yesterday. A cycle of natural avalanches ran on wind loaded slopes late on Saturday and into Sunday. Northerly aspects were the most active during this period. Expect to find wind slabs on many aspects near and above treeline today. The deepest drifts and most dangerous conditions can be found on loaded slopes facing northwest though east at higher elevations. With a decrease in wind speeds, these slabs will slowly start to settle and bond. For today though, triggered avalanches remain a concern on wind loaded slopes and they have to potential to be large and destructive on those higher elevation northerly aspects. At lower elevations, numerous old persistent weak layers continue to plague our snowpack. The shady and sheltered slopes facing the northern half of the compass are the most problematic. Although they were buried over a month ago, several layers of surface hoar can be found in the middle of the snowpack that are still reactive and a concern for triggered avalanches in isolated areas. Test results in several locations around the Aspen zone last weekend were still showing some fast clean shears on these layers. Areas of the zone with shallower average snow depths now also have some layers of concern at the bottom of the snowpack. Colder temperatures during the month of January weakened the snowpack in these areas and started to form some depth hoar in that lower snowpack. On isolated lower elevation slopes, this depth hoar layer may now be triggered on some slopes. Areas like the Castle Creek Valley and Independence Pass are more prone to avalanches failing in this lower weak layer. An avalanche was reported to the office from this past weekend near the Markley Hut that likely failed on one of the mid or lower snowpack weak layers. It was triggered on a steep northeast facing slope below treeline that caught and partially buried four skiers while they were skinning up the slope. Two of them were able to self rescue and dig out their partners afterwards. No injuries occurred in this incident. Weather Discussion for 11,000ft Issued: 02/22/2011 12:24 PM by John Snook A band of clouds will sweep across the northern zones this evening possibly generating a period of light snow not amounting to more than an inch. Relatively weak west-southwest upper-level flow with seasonable temperatures lasts through Wednesday. Expect gusty winds for the usual windy locations in the Front Range zone. The next storm system arrives late Wednesday afternoon with increasing clouds and winds backing toward southwesterly. Light mountain snow falls from Wednesday night into Thursday morning favoring southwest facing aspects. Accumulations look unimpressive with several inches possible for the most favored locations - latest computer models are indicating even less. Strengthening zonal (westerly) flow follows for the remainder of the week with stronger winds and an extended period of unsettled weather. Embedded moisture will generate periods of orographic snow through the weekend favoring the Northern and Central Mountains. Individual storms do not look strong, but snow could add up with successive waves of moisture.