Carson Pass near Frog Lake

We checked the NOAA weather forecast for Carson Pass area the night before and noted that there would be new snow and a strong south wind. We knew there would be north aspect wind loading. We discussed our plan for the next day. We needed to start before the SAC forecast would be out the next morning since I need to be at work at 9:00 so we considered how we would evaluate the snowpack and how we would make decisions along the way. Our plan was to skin to Elephants back and evaluate conditions along the way. Riding Elephants back from the north shoulder was plan A. The three of us skinned from Carson Pass snow park toward Frog Lake. Breaking trail, there was about a foot of very light, new snow. Once Elephants back was in view we could see strong winds whipping the top of the mountain and figured that it would be even more wind loaded there than at the lower elevation, treed area, above Red Lake. We decided to snowboard down toward Red Lake from near Frog Lake. We went to a cool and beautiful gully we had previously ridden. The gully was about 300 feet long and opened up to a flat area at the bottom. The gully faced pretty much directly north and had about a 35 - 40 degree slope. We noted that there was a convex rollover near the top of the gully and it presented an avalanche risk with the new wind loaded snow. We decided to have one person snowboard at a time, with the other two people watching the rider. Since the gully rolled over and wrapped around, I perched on the rock cliff to get a good view. The first rider snowboarded down and it was fine for the first couple of turns. Then the avalanche started to go. More snow released from the where the snow touched the rocky cliff that I perched on. The rider tried to snowboard toward the rocks but more of that snow released in that area. The crown (where the avalanche began) was about 10 inches deep and about 40 feet across. After the slide, there were visible cracks on the bed layer. The rider was not knocked down and was fine. We decided to skin back the way we came rather than continue. We kept our eyes on the rider who skinned back up, as they skinned over more gradual terrain to meet us. Lessons learned: there is limited terrain this year with only high elevation snowpack. To us, that means that there might not be terrain we want to ride immediately after new snow+wind loading. The convex rollover was likely the trigger point. Even if that rollover was avoided, if we had all ridden down, we may have encountered similar micro-terrain hazards. (see video in google folder)

Carson Pass near Frog Lake

Quick report

Avalanche