Corn Snow in Johnson Canyon

We toured in Johnson Canyon to see snow conditions on a variety of aspects. When we arrived in the morning, the snow surfaces were firm and indicated an overnight refreeze that was stronger at the lower elevations than the higher elevations. As we skinned uphill, we found we had to shed layers because we quickly got above the temperature inversion and into the warmer air. E aspects soften by 10 am and transitional wet snow existed on these slopes at that time. In the more shaded areas and on northerly aspects the snow surface remained firm and frozen. 

We stopped to dig a pit on a NW aspect and wait for the S-SW-W aspects to soften. Our pit results showed a well-consolidated snowpack with several crusts in it. The Jan 4 layers did not exhibit any signs of lingering weakness. Once we came back out of our hole, we found about 2 - 5 cm (1-2 inches) of soft wet snow on top of a supportable base on S aspects. This snow was not quite corn and it was still a little sticky. We ski cut a few steep test slopes but not enough wet snow had formed by 11 am to see loose wet instabilities. 

The sticky snow on the S aspects led us to try the SW and W aspects where more wind-scoured and wind-packed snow existed prior to this warming. While we skinned up these aspects we could look back at the steeper E aspects where we could see signs of recent cornice failures in the form of cornice chunks and debris on the slopes below the remaining cornices. We did find more true corn conditions descending the SW and W aspects between noon and 1 pm. At that time we found 2-5 cm (1-2 inches) of soft wet snow on a firm supportable base. While these aspects did hold the best conditions, they also had the least amount of snow and numerous obstacles like bushes and rocks have reemerged onto the surface. As we descended below 7000 ft, around 1 pm we again encountered wet sticky snow.