Snowboarder/Skier Triggered Avavlanches Frog Lake Ridge

 A snowboarder and skier toured to the northwest ridge of Round Top. They skied the north side to Winnemucca Lake. The snow condition was wind crusted and icy. The conditions of the snow did not  indicate an unstable snow pack. The weahter was sunny with windy conditions. The winds were blowing 5-10 mph with gusts 20-30mph. They made it down to Winnemucca Lake with no incident. They decided to head to Elephants Back and Frog Lake ridge to check the conditions.  When they arrived at the south end of Frog Lake Ridge, they found similar conditions to Round Top.  The snowboarder went down a slope greater than 40 degs.  The snow conditions below the ridge became soft and no longer wind crusted. The snowboarder made it approximately 1/2 way down the slope and lost his balance. He leaned back raising the front of the board and dug the back of the board deep into the snow pack. This triggered an avalanche. The avalanche propagated approximately 150 feet across the slope. The avalanche appeared to be a wind slab ~3-4 inches in depth. The snowboarder recovered and was able to ride out of the avavlanche path. The avalanche traveled 150-200 feet down slope. The skier waiting above observed the avalanche.  There was still ~ 1/2 the slope that had not slid below him. Believing he may trigger another avalanche if he followed the snowboarders path, he cut across the slope in order to get to lower angle terrain. This cut caused a secondary avalanche that propagated into the first avalanche. The skier remained outside of the avalanche. Both snowboard and skier paths are visible in the photographs.  Based on the depth and length of the avalanche, it is unlikely that either of them would have been fully buried. Although, if snowboarder had fallen it may have been possible for him to have been partially buried. 

Photos:

The first photo shows the secondary avalanche debris field. 

The third photo shows the overall avalanche path and debris field from the primary avalanche.