Avalanche Forecast

Low - Forecast snowfall amounts are uncertain on Tuesday

MONDAY NIGHT: Snow, accumulation 5-10 cm. Alpine temperature -3. Moderate southwest wind.  Freezing level 1200 mTUESDAY: Snow, accumulation 10-20 cm. Alpine temperature -2. Moderate to strong southwest wind. Freezing level 1500 m.WEDNESDAY: Flurries, accumulation 5cm. Alpine temperature -3. Light west wind. Freezing level 1300 mTHURSDAY: Flurries. Alpine temperature -2. Moderate to strong southwest wind. Freezing level 1400 m.

Recent reports indicate explosives controlled storm slab avalanches running to size 2 on Monday on southerly aspects at tree line and in the alpine. Expect to see the likelihood of triggering storm and persistent slab avalanches increase as new snow amounts begin to accumulate Monday night through Tuesday.

Until today the primary concern was the layer below last week's storm snow accumulations; that would be the Dec 09 (date it was buried) layer of facets (sugary crystals), surface hoar (feathery crystals) and a sun crust on south aspects all about 60 cm deep. After the latest storm Monday night into Tuesday, the Dec 09 will be 70-80 cm below the surface, as well as some new storm & wind slab issues (say within 30 cm of the surface, deeper in wind loaded pockets). Although 10 or 15 cm of new snow daily often won't start a natural avalanche cycle, it looks like we're getting real close to tipping the balance. The Dec 09 layer, it's primed; recent "sudden" snowpack test results and remotely triggered avalanches indicate it remains a critical layer. If the forecast storms materialize I expect this layer may wake up as we continue to build the load on top of it.Lower in the snowpack, previous weak layers from November appear inactive. These deeper layers could possibly cause problems on cold (north facing) slopes at high elevations where the snowpack is thin, but in most places, this is unlikely.