Wind Slabs Developing on Tamarack Peak

The storm seemed warmer than expected as we drove over to Mt. Rose. It was raining at the top of Brockway Summit (~7200 ft) and raining up to about 8000 ft on Mt. Rose Highway. Above 8000 ft, the precipitation changed to snow. 2 to 3 inches of new snow had accumulated at the trailhead since yesterday. We headed up the East Ridge of Tamarack Peak. We felt strong SW winds and gusts in near treeline terrain below the ridge. We could see intense blowing snow on the ridge whenever the clouds parted.

Once we reached the ridge, signs of wind-loading were everywhere. Blowing snow stung our faces, new cornices hung over the leeward slopes, loaded slopes held rippled snow surfaces, and slabs of wind drifted snow had already started to form on the leeward slopes near the ridges. We stayed well away from the new cornices and large wind-loaded slopes. We focused on collecting data from small wind-loaded test slopes where failures would not have consequences. Ski cuts and kicks on these slopes produced shooting cracks and small wind slab failures. The largest of these wind slabs was about 6 to 8 inches deep (or 2 to 4 times as deep as the new snow amounts). These wind slabs will grow in size and extent as the storm continues. The cornices above the test slopes were fragile and would fail well behind their edges.

During our tour, the storm intensity changed several times. The wind was strong enough to push us around on the ridgelines. Snowfall rates were heavy at times and lighter at other times. The temperatures seem to remain fairly constant. Snow levels still hovered around 8000 ft during the drive home.