830 AM PST SAT FEB 24 2007 ZONE AVALANCHE FORECASTS * OLYMPICS, WASHINGTON CACSADES NEAR AND WEST OF THE CREST- ...AVALANCHE WARNING FOR SATURDAY... Considerable avalanche danger above 4000 feet and moderate below significantly increasing Saturday morning and becoming high above 4000 feet and considerable below Saturday afternoon and evening. Slightly decreasing danger later Saturday night and early Sunday, becoming high above 5000 feet and considerable below. Little change in the danger on Sunday, with a slight decrease likely Sunday night. * EAST SLOPES WASHINGTON CASCADES- Considerable avalanche danger above 6000 feet and moderate below early Saturday, increasing Saturday morning and becoming considerable below 7000 feet Saturday afternoon. Slightly decreasing danger Saturday night, becoming considerable above 4 to 5000 feet and moderate below. Little change in the danger on Sunday, slightly decreasing Sunday night. SNOWPACK ANALYSIS In most areas of the Olympics and Cascades near and west of the Cascade crest, including Mt Hood, recent cold showery weather since last Tuesday produced gradually increasing amounts of relatively loose, low density surface and near surface snow. While this recently high quality powder has produced some excellent back country sliding and riding, it lies over some slowly settling, and generally higher density wind slabs that have a weakening bond to several old crusts formed from heavy rain received over a week ago. Recent slow settlement has helped to reduce the potential for triggering these older wind slabs over the crust, and most recent avalanche activity has involved shallow soft wind slabs releasing on weak layers formed during breaks between showers. Nevertheless, with increasing snowfall and strengthening winds in most areas early Saturday, this snow structure is producing a generally increasing danger as higher density snow is deposited over previous weak surface snow, especially at higher elevations where stronger winds are occurring. At lower elevations, more settlement combined with a better initial bond of the underlying slab to the old snow surface and more slowly strengthening winds are helping to produce a slightly lower and overall moderate danger, although both loose and isolated soft slabs remain possible and the danger is also on the rise. Although a similar snow structure exists along the Cascade east slopes, recent lighter amounts of recent snowfall are producing an overall lower danger; however, this danger is also increasing early Saturday, especially at higher elevations close to the crest. DETAILED FORECASTS SATURDAY Light to moderate snow should increase and become moderate to heavy later Saturday morning and afternoon, along with strong winds and slow but limited warming. This should produce a progressively more unstable snowpack with rather sensitive and increasingly dense wind slabs of 1 to 2 feet expected over multiple buried weak layers. As a result, high avalanche danger is likely above about 4000 feet mid-day and Saturday afternoon with increasing and considerable danger below. In the Olympics, Mt Hood area, and Washington Cascades near and west of the crest, natural and human triggered slides should become increasingly likely later Saturday morning and afternoon, especially on steeper wind loaded terrain primarily west exposures near the Cascade passes and north to northeast aspects elsewhere. While most expected avalanches should involve only the most recently deposited wind slabs releasing on previous near surface weaknesses created late this week, some avalanches may trigger isolated deeper slides up to 2 to 4 feet or more which could involve all of the snow above the crust from a week ago. Due to the developing danger and anticipated weather conditions, back country travel in avalanche terrain is not recommended on Saturday. Although a slightly lower danger is expected along the Cascade east slopes, unstable but shallower wind slabs should still become probable on most wind loaded terrain. &&