915 AM PST TUE JAN 8 2008 && ZONE AVALANCHE FORECASTS * OLYMPICS, WASHINGTON CASCADES NEAR AND WEST OF THE CREST- ...AVALANCHE WARNING TUESDAY... High avalanche danger above about 4000 feet and considerable below Tuesday and Tuesday night. Avalanche danger gradually decreasing Wednesday becoming high above 5 to 6000 feet and considerable below. * WASHINGTON CASCADES EAST OF THE CREST- High avalanche danger above about 5000 feet and considerable below Tuesday and Tuesday night. Avalanche danger gradually decreasing Wednesday becoming considerable above 4 to 5000 feet and moderate below. * MT HOOD AREA - ...AVALANCHE WARNING TUESDAY... High avalanche danger above about 5000 feet and considerable below Tuesday and Tuesday night. Avalanche danger gradually decreasing Wednesday becoming high above 6000 feet and considerable below. SNOWPACK ANALYSIS Numerous layers in the upper snowpack have been created since the weekend when strong storm cycles produced wind affected snow that loaded deep lower density snow layers. This was followed by very low density snow of some 3 to 8 inches deposited early Monday with generously light winds. This has created the newest weak layer that is now being overburdened by the heavy snowfall that began early Tuesday morning. This newest snowfall early Tuesday is falling at gradually warming temperatures and very strong crest level winds throughout the Olympics and Cascades. This has deposited denser heavy snow and dense wind slab layers over the weak low density snow layers deposited early Monday, creating an increasing avalanche danger Tuesday. This snowpack structure should make for sensitive triggered or natural slab avalanches becoming likely in the Olympics and Washington Cascades near and west of the crest. Back country travel in avalanche terrain is not recommended Tuesday. In addition to the unstable layers in the upper part of the snowpack, there remains a considerable concern for ongoing trouble layers more deeply buried in the snowpack. These lingering layers include faceted weak snow layers above both a crust formed near Christmas and also the more prevalent crust formed in early December. Numerous slides or field reports are confirming these persistent weak layers. The guides near Washington Pass report improving stability in areas with deeper snow, mainly areas nearer the crest at higher elevations. However in areas with a shallower snow cover, the weak faceted layer above the early December crust remains a concern. Back country skiers on Mt Cashmere near Leavenworth remotely triggered large slab avalanches to these layers late last week as reported on the FOAC web site. Deep natural avalanches on the Christmas crust were seen at Alpental on New Years Day. The Crystal Mountain patrol reports that skiers in Silver Basin triggered a large 1 meter deep slab in facets on the Christmas crust on Sunday on a 45 degree northwest aspect. So these layers may still be sensitive especially to large triggers such as groups or perhaps snowmobiles. This more deep instability is hard to predict just when or what trigger is needed to initiate a slide. Therefore, we would recommend traveling one at a time in any exposed areas, areas with a shallow snow cover or east of the crest, or travel on ridges and lower angle slopes. TUESDAY AND TUESDAY NIGHT Moderate to heavy snowfall and strong south to southwest crest level winds are expected Tuesday along with a gradual warming trend. This should build new unstable layers, especially on lee slopes and higher elevations near ridges. Natural or triggered avalanches should be likely Tuesday. Some slides initiating in new near surface unstable weak layers may step down to older deeply buried weak layers likely near either the Christmas crust where present or the early December crust now down 3 to 7 feet or more depending on location. It should also be noted in areas where a shallower snowpack exists such as east of the crest, or near thin areas in the snowpack possibly near underlying rocks outcrops, it may be possible to trigger slab releases down to the early December crust and these could be large and devastatingly dangerous slides. Back country travel is not recommended in avalanche terrain on Tuesday. Travel should be confined to more shallow angled slopes well away from steep open slopes above. It is also generally safer to travel on slopes with denser tree cover to help anchor the snow and protect from wind deposited snow. WEDNESDAY AND WEDNESDAY NIGHT Decreasing light snow showers early Wednesday with diminishing winds. Further decreasing winds and partial clearing expected later Wednesday. This should allow for slow settlement of recent unstable layers and a gradual decrease in danger. However, at higher elevations and near ridges, unstable layers should remain likely and therefore travelers are urged to use extra caution Wednesday. Increasing rain or snow late Wednesday night at gradual warming should again lead to an increasing danger by Thursday. &&