Unlimited Crust

Today Clancy asked, “Exactly how high does the 2/1 crust go?”  We set out to the Flathead to find out. We found:

• The 2/1 crust extends to at least 7800’ our highest point. There it was half an inch thick but still very hard and supported our weight on skis. Below 7000’ the 2/1 crust was 2 inches thick and very hard. The 2/5 crust phased out at ~7000 ft
• All wind slabs and cornices were capped with 2/1 crust. We initiated one long running D1 from the ridge top and several very small sloughs from steep slopes below where the new snow was more reluctant to move.
• We experienced no cracking or whumphing. Recent avalanche activity was limited to around one dozen D1-1.5 loose dry slides - some of which ran this afternoon. While some of these ran several hundred feet, they did not entrain enough snow to threaten a rider except where terrain traps were present. We also noted 7 D1-2 wet slides that likely ran during the 1/31-2/1 warming event.
• 2 inches of snow at low elevation. Alpine fetches had 4-12 inches of low density snow above the 2/1 available for transport. Lee slopes had 4 inches of low density snow which will underlay any new wind slabs that form during the incoming storm.
• West winds picked up at ridge tops after 1pm. Through the afternoon we observed intermittent moderate blowing snow at upper elevations.
• We had a propagating result with hard force in our test pit on a middle elevation slope. The propagation was in a layer under the 2 inch thick 2/1 crust.
• Video Here.

We felt comfortable skiing slopes around 35 degrees from 7300 ft to 6000 ft, however, we stayed on concave slopes away from trigger points and skied one at a time. Below 6000 feet we skied slopes over 40 degrees with only 2 turns separating skiers.