We went to the Noisy Basin area to watch the storm blow in and the danger rise, but we were short on time. Fortunately, that was not a problem. It helps to think about our afternoon as a play-by-play. The timing gives it context.
11:00: Leave the truck. Icy road. No new snow. Scratchers down on the sleds. The rain on Groundhog's day has eaten away a lot of the snow below 4,000' and there's a lot of bare ground.
11:45: Leave the sleds to start up the ridge. At 5,300' there's about 5" of snow from the groundhog storm. Calm winds, not snowing.
12:00: First new snowfall and winds, both light. We have no luck stomping on small test slopes. We identify persistent weak layers buried a foot down in 2 snow pits (east and west) but don't get propagation in our tests.
12:45: Snow and wind have picked up. We can trigger harmless slabs below tiny, but growing cornices on leeward test slopes. Some of these break 30 feet across from one stomp, though they're only a few inches deep.
1:15: It's snowing an inch per hour. Moderate winds are blowing snow consistently across the ridge. We get shooting cracks from our skis on the ridge.
2:00: At 6,300' we see the newest layer of some cornices fall off and trigger a few small slabs below. I'm wondering why I haven't seen any signs of instability on buried weak layers and decide to pop over the ridge on a low-angled slope near one of the cornices. I want to dig and see if the weak layers are still waiting on slopes that are going to be getting wind loaded. I start digging and that remotely triggers a 6" deep slab on the small slope above me. Not gonna dig here anymore.
2:45: The slabs we're triggering on test slopes are getting bigger. We trigger some small sluffs on steeper, sheltered test slopes. There are periods where it's snowing more than an inch per hour. The winds are still blowing the soft new snow and building slabs. We decide we're getting out of here, back down the same ridgeline we came up.
2:50: 6,500'. I give a final test slope the stomp. I kick off a small wind slab that steps down 2 feet deep to a layer of buried surface hoar. It propagates about 30' across, which is the full width of my little slope.. The avalanche doesn't grow large enough to bury or kill a person, but I know what more snow and wind can do if the weather keeps up.
3:30: 5" of new snow sitting on the sleds when we get back. 5" in 3 and a half hours. It's snowing less intensely and there's less wind as we lose elevation. There's 3" of new snow on the road all the way back to the truck.
To 6500'
Triggered by digging a snow pit.
6" wind slab stepped down to buried SH layer 40cm down.
