16 February 2007

 Good morning. This is Ron Johnson with the Gallatin National Forest
 Avalanche Advisory issued on Friday, February 16, at 7:30 a.m. 

 MOUNTAIN WEATHER

 During the past 24 hours, 1-3 inches of snow fell in the mountains
 around Bozeman and Big Sky, 4-6 inches fell in the mountains around
 West Yellowstone and 6-8 inches accumulated in the mountains around
 Cooke City. This morning, winds are ripping across southwest Montana.

 At 4 a.m., westerly ridgetop winds were gusting to 50-70 mph. Mountain
 temperatures were in the upper teens to low 20s F. Today, strong
 westerly winds will continue to blow 30-50 mph, mountain temperatures
 will be in the 20s F. and scattered snow showers will produce 1-3
 inches of new snow.

 SNOWPACK AND AVALANCHE DISCUSSION

 The Bridger, Gallatin and Madison Ranges including the Lionhead area
 near West Yellowstone, the mountains around Cooke City and the
 Washburn Range:

 New snow, strong winds and a weak snowpack means a HIGH avalanche
 danger exists on all slopes steeper than 35 degrees. A CONSIDERABLE
 avalanche danger exists on less steep slopes. A High avalanche danger
 means avalanches are likely. Travel in avalanche terrain including
 avalanche runout zones is not recommended.

 Yesterday, Doug, Karl and I were in the northern Bridger Range. We
 didnt dig snowpits or conduct stability tests because we saw
 evidence of recent avalanches and heard the snowpack collapse
 under our skis. Thats all the information we needed about the snow
 stability. We didnt take photos or shoot video clips because the
 camera batteries were dead. We didnt approach any steep slopes because
 we were scared. This week both Karl and Doug triggered avalanches from
 low angled slopes. Doug triggered a large avalanche in the Bridger
 Range and Karl triggered avalanches on Lionhead, near West
 Yellowstone. These avalanches released when weak layers of faceted
 snow collapsed and fractures propagated to adjoining slopes that were
 steep enough for the snow to slide. We decided it was prudent to
 avoid avalanche terrain and avalanche runout zones because we were
 scared.

 Yesterday, ski patrollers at Big Sky and Bridger Bowl released
 avalanches on steep wind-loaded slopes. Wednesday, folks in the
 northern Gallatin Range saw evidence of recent avalanches on steep
 west facing slopes. This week, weak layers
 of surface hoar buried 1-2 feet deep in the mountains around West
 Yellowstone produced clean and easy fractures. In the mountains around
 Cooke City, surface hoar buried 1-2 feet deep also exists and with
 the addition of yesterdays 6-8 inches of new snow could be primed to
 fracture. All these observations combined with todays forecast of
 strong winds means avalanches are likely, especially on steep slopes
 and on any recently wind-loaded slopes. Avoiding avalanche terrain
 including low angled slopes attached to steeper slopes is recommended.