230 PM PST MON JAN 28 2008 && ZONE AVALANCHE FORECASTS * OLYMPICS- WASHINGTON CASCADES- MT HOOD AREA- ...AVALANCHE WARNING FOR EARLY TUESDAY MORNING THRU TUESDAY NIGHT FOR THE OLYMPICS, WASHINGTON CASCADES AND MT HOOD AREA... CONSIDERABLE avalanche danger above 4000 feet and MODERATE below Monday afternoon and evening. Gradually increasing danger Monday night. Significantly increasing danger early Tuesday becoming HIGH below 7000 feet. Further increasing danger later Tuesday morning through afternoon remaining HIGH below 7000 feet with natural or triggered slab avalanches likely. Slightly decreasing danger Tuesday night. SNOWPACK ANALYSIS Varying amounts of weak low density snow ranging from about 8 to 20 inches have accumulated since Saturday. The most recent 6 to 12 inches of snow has fallen with generally light winds and very cold temperatures. This weak unconsolidated very low density powder snow is overlying previously deposited weak snow or has buried a surface hoar layer formed earlier in the week during fair weather. Below these surface layers, most areas have highly variable underlying snow pack structure depending on locations, aspect and elevations. The underlying snowpack mainly consists of a variety of crusts caused by wind or sun. In areas void of crusts underlying snow is mainly firmer wind affected or settled older snow. No avalanche activity has been reported Monday as most areas have yet to form a significant slab layer in the upper snowpack. Numerous field tests Sunday including the Mt Baker, Stevens, Snoqualmie, Mission Ridge and Crystal Mountain areas indicated the presence of the widespread weak layers in the upper snowpack. However most areas lacked a surface slab layer or cohesive layer capable of propagating fractures. These conditions are expected to change quickly in the near future! The exception was the Mt Hood area which received much stronger winds than the Washington Cascades or Olympics Saturday night and Sunday and the avalanches seen Sunday reflected this. Explosive control results Sunday at Mt Hood Meadows produced widespread 2 to 4 ft slabs running full path and fast on weak snow above older firm snow. These conditions are expected to develop throughout the forecast region by Tuesday. The current snow pack structure is ripe for a significant increase in danger when strong winds and/or significant loading occur. Smooth crusts or harder old snow will act as sliding surfaces. Weak low density snow, buried surface hoar or near surface faceted snow will act as weak layers. All that is needed is for the missing ingredient of an overburdening slab to develop. These destabilizing conditions are expected to develop overnight and early Tuesday and this should cause a significant and widespread increase in the present avalanche danger. Back country travelers are urged to take these expected changing conditions into consideration as the present powder snow conditions can quickly become very unstable with the affects of wind and loading. MONDAY AND MONDAY NIGHT Monday afternoon and night: Occasional light snow showers Monday afternoon with gradually increasing winds. Further increasing strong winds Monday night along with increasing light to moderate snow should cause an increasing danger. New unstable wind slabs should rapidly build Monday night over a variety of weak underlying layers. TUESDAY AND TUESDAY NIGHT Tuesday: Heavy snow and very strong winds early Tuesday should cause widespread high avalanche danger. Natural or triggered slab avalanches should become likely early Tuesday and persist through the day as unstable slab layers become larger. The present weak surface snow conditions should lead to a rapid and significant increase in the danger early Tuesday. Therefore back country travel in avalanche terrain is not recommended Tuesday. By Tuesday night, slowly decreasing snow and gradually decreasing winds along with expected earlier natural avalanche releases should allow for a slow decrease in danger. &&