830 AM PST FRI FEB 29 2008 && ZONE AVALANCHE FORECASTS * OLYMPICS, WASHINGTON CASCADES NEAR AND WEST OF THE CREST, MT HOOD AREA- Friday morning: LOW avalanche danger below 7000 feet Friday afternoon and night: danger increasing Friday afternoon and becoming CONSIDERABLE ABOVE 4 to 5000 feet and MODERATE below Friday night Saturday: danger further increasing and becoming CONSIDERABLE below 7000 feet late Saturday, except locally HIGH on northeast through southeast facing slopes Saturday night: danger gradually decreasing late Saturday night and early Sunday * EAST SLOPES WASHINGTON CASCADES- Friday morning: LOW avalanche danger below 7000 feet Friday afternoon and night: danger increasing and becoming CONSIDERABLE ABOVE 6000 feet and MODERATE below Saturday: danger further increasing and becoming CONSIDERABLE above 4 to 5000 feet and MODERATE below late Saturday with greatest danger on northeast through southeast exposure slopes Saturday night: danger gradually decreasing late Saturday night and early Sunday * SUNDAY OUTLOOK- Sunday: slightly increasing danger expected on sun exposed terrain, otherwise slowly decreasing danger on shaded terrain Sunday night: decreasing danger early, then gradually increasing danger early Monday SNOWPACK ANALYSIS In most areas a combination of snowpack settlement, little or no precipitation since last weekend, and some limited refreezing overnight are helping maintain a generally stable snowpack and generally LOW danger below 7000 feet early Friday. However as a result of recent mostly fair skies and relatively high freezing levels, surface snow conditions in the region vary widely and range from an increasing surface crust or soft moist surface snow on most previously sun exposed terrain to well settled and relatively firm recycled powder or slightly faceted near surface snow on previously sun shaded slopes. These surface snow layers lie over an increasingly firm, mostly stable and relatively deep base that ranges from about 4 to over 14 feet, depending on location. Fortunately in most locations, the old more deeply faceted layers produced during cold weather in December and January have been bridged by several strong crusts or harder wind slab layers and should not contribute to current or expected future avalanche danger. However, in some higher wind exposed locations, the magnitude of earlier faceting is rather evident and such weakening may become more of a concern during future spring warming or sustained heavy rain events. DETAILED FORECASTS FRIDAY, FRIDAY NIGHT Considerable mid and high clouds and scattered showers are expected in the Olympics and north-central Washington Cascades Friday morning along with increasing high clouds in the southern Cascades and Mt Hood area. While gradually increasing ridgetop winds and slow cooling are also expected, little surface snow remains available for wind transport and hence this weather should maintain current generally LOW avalanche danger. However, increasing light rain or snow should slowly spread south and eastward Friday afternoon, becoming moderate to heavy late Friday afternoon and evening, along with moderate ridgetop winds and further cooling. While initially a relatively good bond is expected between the old snow surface as rain changes to snow below 4 to 5000 feet, a weaker bond is expected at higher elevations where snow should start after surface snow begins to refreeze. This should result in a CONSIDERABLE avalanche danger above about 4 to 5000 feet and MODERATE danger below, with greatest danger developing on north, northeast and east exposures where shallow but increasing winds slabs of 6- 12 inches are probable. SATURDAY, SATURDAY NIGHT Light to moderate showers late Friday night and early Saturday should increase mid-late Saturday morning and afternoon, with a Puget Sound convergence enhancing snowfall near Stevens Pass Saturday morning and Snoqualmie Pass Saturday afternoon and evening before diminishing later Saturday night and early Sunday. Along with moderate winds and low freezing levels, this weather should continue to gradually increase the generally CONSIDERABLE avalanche danger, especially on northeast through southeast exposures where locally HIGH danger is expected. Increasingly cohesive wind transported snow mid-day and Saturday afternoon should be deposited over some lower density layers developed during lighter showers early Saturday, with some human triggered 12-18 inch soft slabs becoming probable to likely later Saturday. Although recently very nice weather has brought thoughts of spring to many, back country travelers are urged to realize that winter isnt over til its over and use increasing caution in avalanche terrain on Saturday with stability tests strongly encouraged. Gradually decreasing winds and showers later Saturday night and early Sunday should allow for a slow decrease in the danger. SUNDAY, SUNDAY NIGHT Further decreasing clouds with scattered light showers ending early Sunday should be followed by partly to mostly sunny skies Sunday morning, and considerable filtered sunshine through increasing high clouds Sunday afternoon. Along with generally decreased and relatively light winds and slight warming, mainly in the south, this weather should allow for a slowly decreasing danger on most lee slopes as recent wind slabs begin to settle. However, a locally increased danger is probable on sun exposed terrain as strengthening early March sun weakens and melts snow from tree boughs and rock faces, thus increasing the potential for both natural and human triggered, loose and isolated slab slides on the slopes below. Clouds should increase and lower Sunday night, with light rain or snow redeveloping in the Olympics and north-central Cascades early Monday. Along with increasingly strong ridgetop winds and lowering freezing levels, this should lead to increasing avalanche danger Monday morning. &&