0830 AM PST SAT DEC 29 2007 && ZONE AVALANCHE FORECASTS * OLYMPICS, WASHINGTON CASCADES NEAR AND WEST OF THE CREST, MT HOOD AREA- ...AVALANCHE WARNING FOR SATURDAY NIGHT AND SUNDAY... Considerable avalanche danger below 7000 feet Saturday morning with danger accentuated on southeast through northeast exposures at all elevations. Danger gradually increasing Saturday afternoon and significantly increasing Saturday night, becoming high below 7000 feet. High avalanche danger below 7000 feet continuing on Sunday, especially on southeast through northeast exposures. Slowly decreasing danger expected later Sunday night and early Monday. * EAST SLOPES WASHINGTON CASCADES- ...AVALANCHE WATCH FOR SUNDAY... Considerable avalanche danger below 7000 feet Saturday morning. Danger slowly increasing Saturday afternoon and night and becoming high above 5 to 6000 feet and considerable below, except locally high on most wind loaded southeast through northeast facing terrain. High avalanche danger above 4000 feet and considerable below on Sunday. Danger slowly decreasing later Sunday night and early Monday. SNOWPACK ANALYSIS Recent large amounts of new relatively low density snow are continuing to slowly settle, but several buried weak layers exist above the most recent and now slightly faceting Christmas eve crust, and these have combined with some wind transport to help maintain a considerable avalanche danger below 7000 feet, especially on southeast through northeast exposures. While most field reports indicate primarily small 4 to 12 inch soft slabs releasing on lower density snow received during lighter winds and showers and cold temperatures last Wednesday, some isolated but larger slides have still been triggered by both explosives and skiers on the weakening and faceting crust that developed early last week, with some of these slides reaching 2 to 3 feet or more. Recent stability tests on the FOAC site and from various professional ski patrollers indicate the existence of some easy shears both within the new snow from the past few days and near the Christmas eve crust. Fortunately there have been no recent reports of slides releasing down to the old faceted early December crust; recent snow settlement and gradual insulation of this layer from colder surface temperatures may help this layer to very slowly stabilize and strengthen. However, this troublesome and weak bed surface is closer to the surface along the Cascade east slopes and it may still be relatively close to the surface on steeper slopes that have already released on this old crust. Hence, while it is a slowly decreasing problem in most locations, it may still be a more immediate concern in the overall shallower snowcover along the Cascade east slopes, especially in the northeast Cascades where only limited warming occurred during much of December. And it may once again become a concern west of the Cascade crest if future heavy rainfall occurs. Finally, please note that the large amounts of unconsolidated snow pose a serious suffocation threat, especially if falls occur near a tree well. As a result of all of these snowpack conditions, back country travelers are urged to exercise increasing caution Saturday, choose routes wisely and keep close watch on friends, especially if they fall. DETAILED FORECASTS SATURDAY Light to occasionally moderate snow or snow showers should increase later Saturday morning and afternoon, along with increasing winds and slight warming. This should produce a slow increase in the avalanche danger through further slow loading of existing wind slabs. Natural avalanches should be possible and human triggered slides probable, especially on steeper wind loaded terrain which includes most southeast through northeast exposures. Travelers are urged to use increasing caution in avalanche terrain Saturday, with snow stability tests and proper route selection strongly encouraged. SATURDAY NIGHT, SUNDAY, SUNDAY NIGHT Heavy to very heavy snowfall and very strong winds are expected Saturday night and Sunday, especially in the Olympics and Cascades near and west of the crest. This should produce a significant danger increase as increasingly sensitive and progressively larger wind slabs develop on lee slopes. Shooting cracks, extensive fracture propagation and sympathetic slides should become likely late Saturday and Sunday, and increasingly large cornices may be very sensitive as well. Avalanches which initiate in the most recently deposited wind slab snow may step down to older weaker layers, with more isolated larger slabs possibly reaching the old early December crust, especially in higher terrain along the Cascade east slopes. While the expected very strong winds may also scour some wind exposed terrain to higher density snow near the old crust from earlier in the week and produce a wind hardened snowpack with an associated lower danger, nearby lee slopes should be heavily loaded, with wind deposits and associated fractures possibly developing lower in the path than normal. As a result of the anticipated poor weather and visibility conditions as well as the increasingly unstable snowpack, back country travel in avalanche terrain is not recommended late Saturday through Sunday, and travel should be confined to lower angle terrain not connected to steeper terrain above. Slowly decreasing showers and winds later Sunday night and early Monday should allow for a very slow decrease in the danger as new wind slabs begin to settle. &&