INTRODUCTION: This is Stan Bones with the backcountry avalanche advisory issued on Tuesday, February 19, 2008, at 5:30 AM by the U.S. Forest Service Glacier Country Avalanche Center for the Glacier Park and Flathead and Kootenai National Forest areas. HAZARD ANALYSIS Between 5,500' and 7,500' elevation the avalanche danger is currently rated MODERATE. Below 5,500' we're rating the avalanche danger LOW. These danger ratings expire at midnight Tuesday, February 19th. The outlook is for the avalanche danger to remain near current levels through Thursday, unless rapid solar warming occurs, in which case we could see an increase in both wet loose snow and wet slab avalanche activity. Because of the general nature of this advisory message, each backcountry party will always need to make their own time and site specific avalanche hazard evaluations. WEATHER ANALYSIS: This past week Northwestern Montana received two shots of new snowfall. The first and most significant was on Tuesday a week ago when our central and eastern mtn. ranges picked up 1.5 to almost 2 inches of new snow water equivalent. The western mtns. on the Kootenai received half to a third of that amount at between 0.5 to 1 inch of new snow water equivalent. Last Friday was our second shot when again the central and eastern ranges were the most favored at nearly an inch of new snow water equivalent. The Kootenai mtns. as previously, lagged behind at 0.2 to 0.7 inches of snow water equivalent. Early in the week winds were strong, blowing predominately from the west. By Saturday these winds started dropping as a very robust high pressure ridge began building over the region. Temperatures have remained below freezing throughout the week. Friday into Monday generally saw a cooling trend as the high pressure ridge built. This cooling occurred even though the spread between maximum and minimum. temperatures increased as clearing skies developed. . SNOWPACK ANALYSIS: Our backcountry observations Monday were on Peters Ridge and above Picnic Lakes, both in the north Swan Range, NE of Bigfork. We received a report on Saturday from the Rescue Creek area in the Flathead Range and the Middle Fork drainage. In that report we learned of a series of backcountry skier triggered, wind loaded, slab avalanches that initially buried a single individual nearly to the waist. In a secondary avalanche he was buried uninjured up to his shoulders. In our snowpits and observations on Monday we were finding moderating snow instability. This is in response to the dry conditions and dying winds of the high pressure ridge. In shear tests we are still seeing instability associated with the recent wind loading events and that have been so common much of the winter. Even though these instabilities are requiring increasing force to produce failure, they continue to frequently fail smoothly and with energy. That is worrisome, as is the development of surface hoar and other surface facet weaknesses produced by the cold, clear night conditions. These weak surface crystals could play a role in future avalanche activity. AVALANCHE - INSTABILITY DESCRIPTION: We're currently rating the avalanche danger between the elevations of 5,500 and 7,500' as MODERATE. Unstable slab layers are possible, particularly on steep, open, wind loaded terrain. Natural avalanches are unlikely, but human triggered avalanches are possible. Backcountry travelers should use caution, should always carry and know how ot use avalanche safety equipment, and expose no more than a single person to danger at a time. Below 5,500 ft. elevation we're rating the avalanche danger as LOW. A more shallow snow there is often anchored by vegetation and terrain features and generally stable with only isolated areas of instability. Natural avalanches are very unlikely, while human triggered avalanches are unlikely. Backcountry travel is generally safe, but normal caution is still advised on any steep, open slope. WEATHER FORECAST & AVALANCHE OUTLOOK: The weather forecast is for the current high pressure ridge to persist at least into Thursday. Dry conditions are forecasted for the period. High temperatures are expected to be well above freezing under generally sunny skies during the day, but plunging at night as clear conditions mostly persist. Depending upon how these conditions balance against each other and how winds play in the equation we could see the current level of avalanche danger persist. If heating increases to a dominate role, we would expect to see at a minimum an increase in wet loose snow avalanche activity. Although relatively slow in speed these slides can involve significant quantities of heavy wet snow. Significant warming can also trigger wet slab avalanches on more deeply buried weaknesses. Watch also the condition of the current existing weak surface snow. If persisting and with future loading this could also be the source of new instability. The next regularly scheduled update of this advisory message will be Friday, February 22nd.