845 AM PST SAT FEB 02 2008...AMD && ZONE AVALANCHE FORECASTS * OLYMPICS, WASHINGTON CASCADES NORTH OF MT RAINIER- HIGH avalanche danger 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. Gradually decreasing avalanche danger Sunday, becoming HIGH above 5 to 6000 feet and CONSIDERABLE below later Sunday. * WASHINGTON CASCADES FROM MT RAINIER SOUTHWARD, MT HOOD AREA- ...AVALANCHE WARNING CONTINUES THROUGH SATURDAY NIGHT... HIGH avalanche danger below 7000 feet through Saturday night. Gradually decreasing avalanche danger Sunday, becoming HIGH above 5 to 6000 feet and CONSIDERABLE below later Sunday. SNOWPACK ANALYSIS...AMD... Additional moderate to heavy snowfall was received in most areas on Friday, heaviest in the southern Washington Cascades and Mt Hood area, with 24-hour amounts ranging from about 6-8 inches in the north, 6-10 inches in the central Cascades, and 8-16 inches in the south. 7-day totals since last weekend now range up to 6-9 feet. Along with moderate winds and generally low but slightly fluctuating freezing levels throughout most of the snowfall, this weather created an increasingly unstable and very dangerous snowpack structure Thursday and Friday. Although recently decreased loading rates and increasing settlement have allowed for a slight decrease in the danger in the Olympics and Cascades north of Mt Rainier, human triggered slides remain probable to likely in most locations, and an Avalanche Warning continues for the southern Washington Cascades and Mt Hood area where further heavy snowfall is likely. In most areas, several weak layers exist within or just under the most recent heavy snowfall due to variations in wind speeds and precipitation rates during the past 48-72 hours, and these have produced significant slide activity within the upper 1-3 feet of new snow. The sustained and almost continuous heavy snowfall since last weekend 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. Although much of the recently reported natural and controlled slide activity has involved only the most recently deposited new snow, some larger slides have reached more deeply buried weak layers during the past 24 hours. Examples include 5-8 ft explosive controlled slabs near Snoqualmie Pass and Mt Hood Meadows, most probably releasing on facets near the mid-Jan crust. Also a moderate angled slope called Neverslides did, releasing 3-4 ft deep from explosives on Friday. This 2500 ft elevation, 33 degree cut bank slope affecting I-90 fractured 100% of the path over 250 ft wide and deposited considerable debris on the at-the-time closed highway. Also, a controlled large slab release from the Denny Mt paths became airborne and destructive, depositing both timber and debris on the elevated west bound lanes of I- 90 while also taking out a weather station. All in all, a pretty unstable snowpack. Please also note that the very large amounts of relatively low density snow have not only produced a substantial avalanche danger, but have also made any snow travel very difficult. Foot penetration off the trail was reported as reaching shoulders to head depth early Friday. While some recent settlement has helped to slightly reduce both the avalanche danger in the Olympics and Cascades north of Mt Rainier and human penetration into the deep unconsolidated snowpack, suffocation continues to be a very real possibility from a fall, especially near tree wells and even within developed ski areas. As a result of continuing 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 SATURDAY, SATURDAY NIGHT...AMD Light to moderate snow should increase in the southern Washington Cascades and Mt Hood area early Saturday, with light to moderate snow and slightly increasing winds spreading slowly northward later Saturday morning and afternoon. 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 continue to 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 and additional lighter amounts of new snow should help 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 recreating or big air landings, especially in steeper wind loaded terrain not showing evidence of recent avalanche activity. Stability tests are strongly encouraged with conservative decision making remaining critical as our dangerous snowpack makes very slow strides toward stabilizing. &&