Lawine

Borah

VandenBos (off duty)
Auf der Karte ansehen
Beobachtungsfoto 1

Quick report

This was an off duty walk in the hills on my way to a seminar in Bozeman. My goals were to move my legs, check quality of the overnight freeze, and to get a sense for what the snow was doing in the lost. 

I traveled through a fair bit of terrain and did not experience cracking or collapsing related to a weak layer. On some slopes on solar margins, where crusts existed at the surface, the crust was unsupportable and I dropped into the weak snow underneath.

Weather

Clear skies above in the morning, with a thick band of mid level cumulus visible to the west. I felt a few RDs (rain drops) around 0930 before an intense convective band of graupel rolled through around 1000. Variable mid level clouds brought periods of sun and clouds. Winds were variable in strength and direction.

Snowpack

I did not encounter a wet snow problem. Clear skies allowed for plenty of longwave radiation to escape the snowpack at night, producing supportable crusts at all elevations despite the slightly above freezing temperatures recorded at weather stations. This is a common spring phenomena. 

No formal observations today, just moving through terrain and looking around. The snowpack in the lost is definitely on the lean side this season. I expect we will quickly loose a lot of low and mid elevation snow and access here  as things get rained on and when we get back into sunny high pressure.

Avalanche

I observed quite a bit of small, wet loose activity from the recent warm up (much of this likely occurred on 3/29, some likely continued on 4/1 and 4/2. There were many larger, older slides apparent in the northern Lost and Pashimeroi. Many of these appear to have failed during the mid-March-meltdown, others failed earlier as dry slabs.