9 AM PST FRI FEB 01 2008 && ZONE AVALANCHE FORECASTS * OLYMPICS, WASHINGTON CASCADES NORTH OF MT RAINIER- ...AVALANCHE WARNING FOR FRIDAY... HIGH avalanche danger below 7000 feet Friday, slowly decreasing Friday night and becoming HIGH above 4 to 5000 feet and CONSIDERABLE below early Saturday. Little change in the danger on Saturday, but slightly decreasing avalanche danger likely late Saturday. * WASHINGTON CASCADES FROM MT RAINIER SOUTHWARD, MT HOOD AREA- ...AVALANCHE WARNING FOR FRIDAY AND SATURDAY... HIGH avalanche danger below 7000 feet Friday and Saturday. * SUNDAY OUTLOOK Gradually decreasing avalanche danger Sunday, becoming high above 5 to 6000 feet and considerable below later Sunday. SNOWPACK ANALYSIS Additional heavy snowfall was received in most areas on Thursday, heaviest near and west of the Cascade crest, with 24-hour amounts ranging from about 8 to over 16 inches and 6-day totals since last weekend ranging up to 5-8 feet. Along with moderate winds and generally low but slightly fluctuating freezing levels throughout most of the snowfall, this weather has created a highly unstable and very dangerous snowpack structure. Several weak layers have developed within or just under the most recent heavy snowfall due to variations in wind speeds and precipitation rates during the past 24-36 hours, and these are expected to produce significant slide activity within the upper 1-3 feet of new snow. However, the sustained and almost continuous heavy snowfall since last weekend has also loaded some very weak layers of faceted snow, buried surface hoar or very low density snow that developed during the mostly clear and cold weather in mid-January. While primary slide activity should involve the most recently deposited new snow, slides which do release may trigger some larger slides reaching more deeply buried weak layers. The potential for some larger releases has already been realized during the past 24 hours, with some 3 to 6 ft natural slabs reported from Stevens Pass, Snoqualmie Pass and the Mt Hood area, along with some timber damage. The very large amounts of relatively low density have not only produced a generally high avalanche danger with both human and naturally triggered slides likely, but have also made any snow travel very difficult. Foot penetration off the trail has been reported reaching shoulders to head depth, and suffocation within this deep unconsolidated snowpack structure is a very real possibility from a fall, especially near tree wells and even within developed ski areas. As a result of avalanche and deep snow travel concerns, back country travel in avalanche terrain is not recommended. Anyone recreating in this current snowpack should have probes, shovels, beacons, extreme caution and a very aware partner; watch each other and stay close together. DETAILED FORECASTS FRIDAY, FRIDAY NIGHT Moderate to heavy snow or snow showers in most areas Friday morning should slowly and briefly decrease Friday afternoon and night. Along with moderate ridgetop winds and relatively low temperatures, this should maintain HIGH danger and a mostly unstable snowpack for much of the day. Further natural and human triggered slides should remain likely on Friday. Although most slides should involve only the most recently received new snow, some deeper and possibly destructive slides are possible, especially on slopes showing no evidence of recent avalanche activity. While a slight and brief decrease in the danger is expected Friday night, any settlement and stabilization should be rather limited. SATURDAY, SATURDAY NIGHT Light to moderate snow should redevelop and increase in the southern Washington Cascades and Mt Hood area later Friday night and early Saturday, with light to moderate snow and slightly increasing winds spreading slowly northward later Saturday morning. This weather should help maintain existing considerable to high danger in the Olympics and Washington Cascades north of Mt Rainier. However, further to the south, the combination of moderate to heavy snow and moderate to strong winds should maintain an Avalanche Warning with generally HIGH danger continuing below 7000 feet. In the Mt Hood area and the southern Washington Cascades from about Mt Rainier southward, further heavy snowfall should load and stress weaker snow layers developed during decreasing showers and winds late Friday as well as a variety of more deeply buried weak layers. While less loading is expected further north, the large amounts of unconsolidated snow received through Friday night should only very slowly settle with additional lighter amounts of new snow helping to maintain considerable to high danger. SUNDAY Generally decreasing showers should spread slowly southward Sunday morning with light showers and some brief partial clearing expected Sunday afternoon. This should allow the recent heavy snowfall and substantial wind slabs to begin to settle and partly stabilize. However, human triggered slides should remain probable to likely in most steeper avalanche terrain, especially on wind loaded northeast to southeast exposures near higher ridges. Considerable caution is advised in route selection and terrain management with the expected danger levels. The current snowpack structure will not be forgiving of mistakes, and will not react kindly to high marking, aggressive recreation or big air landings, especially in wind loaded terrain. Stability tests are strongly encouraged with conservative decision making remaining critical as our dangerous snowpack makes very slow strides toward stabilizing. &&