0845 AM PST Saturday, February 17, 2001 ZONE AVALANCHE FORECASTS..... WASHINGTON CASCADES FROM STEVENS PASS SOUTHWARD. . .OLYMPICS. . . Considerable avalanche danger below 7000 feet gradually increasing Saturday afternoon through Sunday morning, possibly becoming high above 3 to 4000 feet and considerable below. Danger slowly decreasing Sunday afternoon and night and becoming considerable above 4 to 5000 feet and moderate below. WASHINGTON CASCADES NORTH OF STEVENS PASS. . . Considerable avalanche danger above 5 to 6000 feet and moderate below gradually increasing Saturday afternoon through Sunday morning and becoming considerable above 4 to 5000 feet and moderate below. Danger decreasing Sunday afternoon and night and becoming considerable above 5 to 6000 feet and moderate below. MT HOOD AREA. . . Considerable avalanche danger above 6000 feet and moderate below gradually increasing Saturday afternoon through Sunday morning and becoming considerable above 5000 feet and moderate below. Danger decreasing Sunday afternoon and night and becoming considerable above 6000 feet and moderate below. MONDAY OUTLOOK. . . Gradually increasing danger is expected mid-late Monday, mainly from the central Washington Cascades southward, with relatively little change in the danger further north. SNOWPACK ANALYSIS..... Moderate to heavy snowfall-heaviest in the Olympics and Washington Cascades from Stevens Pass southward--and moderate to strong winds late Thursday and Friday were followed by decreasing showers but continued relatively strong winds late Friday through early Saturday. Although this allowed for a slight decrease from the recent high danger in the south-central Cascades, a considerable danger remains below 7000 feet with unstable wind slabs ranging up to 1 to 3 feet probable in wind loaded terrain- primarily west through northwest facing slopes. During the past 24 hours, field reports indicate significant wind transport of new snow in most areas, and sensitive slides of 1 to 2 feet or more quickly ran long distances during avalanche control Friday. Although some settlement of these slabs has occurred, many of these newly developing and generally higher density wind slabs were deposited over and remain poorly bonded to weak snow layers or snow surfaces that include an old melt-freeze crust, surface hoar or weak low density snow received early Wednesday. Also, moderate to strong winds early Saturday are continuing to build larger slabs, with some hollow sounding hard slabs likely forming over weak snow below ridges. Finally, recent cold temperatures in the north-central Cascades, Cascade passes and Cascade east slopes should be once again allowing for more faceting and weakening of snow near several buried crusts and near the recent surface snow that had warmed substantially last Wednesday. This faceting should help keep much of the upper part of the snowpack relatively weak, and susceptible to stress failure and fracture if future heavy loading is received, such as that being experienced currently from strong wind transport. Hence surface slide releases of the most recently deposited snow may trigger some isolated larger slides involving all of the snow since early-mid January, with isolated releases of 2-4 feet or more possible in heavily wind loaded terrain. Generally less snowfall received in the north Cascades and Mt Hood areas since mid-week is producing a slightly lower danger, however a similar unstable snow structure exists and a considerable danger exists on lee slopes above about 5000 feet in the north Cascades and above 6000 feet in the Mt Hood area. At lower elevations in these areas less winds are resulting in a moderate danger with smaller slabs possible in wind affected terrain-mainly northwest through northeast exposures near Mt Hood and north through west exposures in the north Cascades. SATURDAY. . .SATURDAY NIGHT. . . Increasing clouds are expected Saturday morning with light rain or snow developing in the south mid-day or early Saturday afternoon, spreading northward later Saturday afternoon and evening. Light to moderate rain or snow is expected Saturday night and early Sunday, heaviest in the south-central Cascades and along the Cascade east slopes. Along with slight warming and moderate winds, this should result in gradually increasing danger as new soft wind slabs are deposited over an already unstable snowpack including some rather unpredictable hard slabs. Greatest danger should continue on northwest through southwest facing slopes near the Cascade passes and northeast through northwest exposures elsewhere, and back country travel is still not recommended on steeper terrain showing evidence of recent wind transport. SUNDAY. . . Although light to moderate rain or snow should decrease and become more showery Sunday morning, further slight warming is also expected with the effects being most pronounced near the Cascade passes. This should help to further slightly increase existing avalanche danger with a high danger possibly developing above 3 to 4000 feet, especially near the central Cascade passes. In areas near the Cascade passes, most slopes have been under the influence of a cold easterly pass flow since early Thursday, and a pass wind shift to briefly warmer westerly may substantially increase the danger as brief wet snow or rain is possible below 3 to 4000 feet. Gradually decreasing winds mid-late Sunday through early Monday along with slightly lowered freezing levels-mainly in the north--should allow for a slow decrease in the danger as new wind slabs slowly settle. However, travelers should continue to assess snowpack stability often and travel on wind loaded terrain is not recommended. MONDAY. . . After a brief decrease in showers and some partial clearing, increasing clouds and light to occasionally moderate rain or snow should spread northward mid-late Monday. However, most of this precipitation should remain in the south-central Cascades and Mt Hood area with only light showers expected further north. Along with only a slight rise in freezing levels and mostly light to moderate winds this should only produce a slight increase in the danger, mainly in the southern and central Washington Cascades and Mt Hood area where further small wind slabs should develop. Further north, mainly light showers and little or no warming are expected to produce little change in the avalanche danger.