####018003541#### WWUS86 KPQR 262022 SABOR Summary Avalanche Forecast for Mt Hood area Northwest Weather and Avalanche Center Seattle Washington 1221 PM PST Sun Feb 26 2012 This forecast applies to back country avalanche terrain below 7000 feet and does not apply to developed ski areas or highways. Avalanche Forecast Mt Hood Area AVALANCHE WARNING SUNDAY Sunday: High avalanche danger above 5000 feet and considerable below. Slowly decreasing danger afternoon and night. Monday: Decreasing high danger above 6000 feet and considerable below. Snowpack Synopsis A very strong very wet storm crossed the Northwest last Tuesday and Wednesday. This cause a widespread avalanche cycle with many large avalanches and Pass closures. At Mt Hood this cycle should have mostly stabilized old snow layers and created a new bed surface for the upcoming storms. Another strong but cooler front then crossed the region Friday night with strong flow continuing to early Sunday. This storm has deposited 15 to 20 inches of snow since Friday. Reports Saturday from Mt Hood Meadows indicated widespread natural or triggered slab releases on a variety of slope aspects. Mostly of the early slabs were fairly soft with weak snow over a crust from last week. Sunday An upper trough will shift east of the area through the day Sunday. This will cause gradually decreasing snow showers and winds at cool temperatures through the afternoon. Showers should end overnight with partial clearing as high pressure rebuilds. The new snow Sunday should continue to add load to numerous recent weak layers or more more deeply buried layers of earlier form slab layers over a strong smooth buried crust layer. Overall, the trend will be for thin shallow weak layers to settle and slowly compress and stabilize though these processes will be slowed due to the cold temperatures. In exposed avalanche terrain we are advising that travel is not recommended in avalanche terrain. Monday High pressure should rebuild over the area Monday to provide a break in the recent storm cycles. Sunshine is expected with light winds and cool temperatures. This should allow recent storm and wind slabs to further slowly settle and stabilize. However, unstable wind slabs should persist in previously loaded areas. Triggered slides may need a little more weight or load to initiate a slide...maybe not the first skier or boarder but the next one. We should not be out of the woods by Monday. Even though sunshine should be out, do not let your avalanche guard down, continue with careful snowpack evaluations, cautious routefinding and conservative decision-making. Sunshine on steeper southerly aspects may cause a locally greater danger. This may cause loose cohesion less snow to become cohesive as the surface layers become more slab like. This should help to make triggered slides more likely on some sun exposed terrain. n/a n/a NWAC weather data and forecasts are also available by calling 206-526-6677 for Washington, 503-808-2400 for the Mt Hood area, or by visiting our Web site at www.nwac.us. Kramer/Northwest Weather and Avalanche Center Seattle Washington References 1. http://www.nwac.us/####018003680#### WWUS86 KSEW 262022 SABWA Summary Avalanche Forecast for Olympics and Washington Cascades Northwest Weather and Avalanche Center Seattle Washington 1221 PM PST Sun Feb 26 2012 This forecast applies to back country avalanche terrain below 7000 feet and does not apply to developed ski areas or highways. Avalanche Forecast Olympics, Washington Cascades near and west of the crest AVALANCHE WARNING SUNDAY Sunday: High avalanche danger above 4000 feet and considerable below. Slowly decreasing danger afternoon and night. Monday: Decreasing high danger above 5000 feet and considerable below. Washington Cascades east of the crest Sunday: High avalanche danger above 5000 feet and considerable below. Slowly decreasing danger afternoon and night. Monday: Decreasing considerable danger above 4000 feet and moderate below. Snowpack Synopsis Another strong storm cycle began Friday with continued light snow showers still going as of early Sunday. Thus far most areas in these zones have received 15 to over 30 inches new snow. Strong crest level winds through early Sunday have continued to build storm slab layers, especially high elevation lee slopes. The strongest winds have ranged from southwest to northwest, however cross loading has also occurred on numerous tangent slopes. Therefore, complex loading and widespread unstable wind slabs are dominating exposed terrain. Sunday An upper trough will shift east of the area through the day Sunday. This will cause gradually decreasing snow showers and winds at cool temperatures through the afternoon. Showers should end overnight with partial clearing as high pressure rebuilds. The new snow Sunday should continue to add load to numerous recent weak layers or more more deeply buried layers of hoar frost over a now deeply buried crust layer. Overall, the trend will be for thin shallow weak layers to settle and slowly compress and stabilize though these processes will be slowed due to the cold temperatures. In exposed avalanche terrain we are advising that travel is not recommended in avalanche terrain. Monday High pressure should rebuild over the area Monday to provide a break in the recent storm cycles. Sunshine is expected with light winds and cool temperatures. This should allow recent storm and wind slabs to further slowly settle and stabilize. However, unstable wind slabs should persist in previously loaded areas. Triggered slides may need a little more weight or load to initiate a slide...maybe not the first skier or boarder but the next one. We should not be out of the woods by Monday. Even though sunshine should be out, do not let your avalanche guard down, continue with careful snowpack evaluations, cautious routefinding and conservative decision-making. Sunshine on steeper southerly aspects may cause a locally greater danger. This may cause loose cohesion less snow to become cohesive as the surface layers become more slab like. This should help to make triggered slides more likely on some sun exposed terrain. n/a n/a NWAC weather data and forecasts are also available by calling 206-526-6677 for Washington, 503-808-2400 for the Mt Hood area, or by visiting our Web site at www.nwac.us. Kramer/Northwest Weather and Avalanche Center Seattle Washington References 1. http://www.nwac.us/