Aspen ===== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, crusts, drifts, facets, high pressure, natural avalanche, orographic, slabs, stress, sugary, surface hoar, weak layers, wind loading, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 1/25/2008 8:45:57 AM Forecaster: Brian McCall Weather Synopsis High pressure is slowly building into to Colorado as the last system moves eastward. The lower portion of the atmosphere remains quite moist, but there is no real mechanism to wring out precipitation. Clouds and snow showers will continue in areas that produce orographic lifting from southwest and westerly flow. I don't expect more and an inch or two to accumulate. Overnight, wind speeds will continue to increase along the northern portions of the Continental Divide and the Front Range, while mild weather develop in the central and southern mountains. The next storm system is forecast to arrive later on Sunday. Weather forecast models have begun to slow the eastward progression of this system, so we will keep a close eye on the timing over the next few days. Weather Friday Night Saturday Saturday Night Temperature(°F) 14-19 2-7 18-23 Wind Speed(mph) 15-25 G35 15-25 G35 15-25 Wind Direction W W WSW Sky Cover Mostly Cloudy Mostly Cloudy Decreasing Snow(in) 2-5 0-2 0-1 Snowpack Discussion Weather stations are showing 3-6" of new snow around the Aspen Zone overnight. The Schofield area looks to have picked up a little more with 8-10" falling there. This storm has not been a big snow producer for the area but wind speeds during the day yesterday and overnight were high enough to transport snow onto lee aspects. S and SW winds blew all day yesterday and loaded slopes facing N-NE-E. Overnight they have switched to a more westerly direction. This wind loading created one small natural avalanche on an E aspect above treeline near the Peter Estin hut. Although it was small, this avalanche is a good indication of some of the tender wind slabs you will find in the backcountry today. Look for some fresh wind drifts on slopes facing N-NE-E-SE, near and above treeline, as you venture out. New storm snow and wind deposited snow will be stressing a couple weak layers in the upper snowpack. Layers of "sugary" facets, feathery surface hoar grains in some areas, and some slick crusts are all getting buried by this new snow. Look for these weaknesses in the upper 1-2 feet of the snowpack. Near and below treeline, a layer of surface hoar buried just over a week ago on SE-S-SW aspects may also start to become a problem. Watch for avalanche activity on this layer, especially in steeper pockets below treeline. Most avalanches that occur today will happen in these upper snowpack weak layers. However..... We cannot have a snowpack discussion this winter without mentioning those persistent, deep weak layers. Although they are becoming difficult to trigger, avalanches do have the potential to step down and become large events. The structure of the snowpack right now inspires VERY LITTLE confidence for bigger terrain in most areas of the Aspen Zone. A stronger layer in the middle of the snowpack may give you a false sense of security but remember that our snow cover in Colorado is highly variable. Find an area where that midpack is thinner and you may find yourself going for an unplanned ride. Avalanches in these conditions are often triggered from lower on the slope where the snowpack thins out and puts you closer to those weak layers. Avalanche Danger With new snow and recent wind loading, we will hold the danger at CONSIDERABLE on north, northeast, east, and southeast aspects near and above treeline. Winds out of the S-SW-W have created some fresh slabs on these easterly aspects. The avalanche danger on all other aspects near and above treeline and all slopes below treeline is rated MODERATE. You need to choose your terrain wisely. Good route finding and the ability to select terrain that is appropriate for the current conditions are two great tools to take with you into the backcountry this season. There is a lot of great riding out there now, but the snowpack demands a lot of respect. Consider the consequences of a wrong decision.