Avalanche at taking mountain

We dropped in west of talking mountain, between talking and cup lake. I was on a splitboard and my partner dan was on skis. We traversed east into rolling powder 30-35 degrees, I came to a steeper section of about 40 degrees. Made a few turns and was followed by what looked like surface sluff, then momements later saw both sides of me moving faster than I was. I announced "avalanche" into the radio, triggered my airbag, was knocked down and slid along on my back about 20 feet toward a small group of trees and pushed my board away from each tree. I came to a stop shortly after in a safer area on the edge of the track. The runout was for another 50' and about 60' wide. Dan observed signs of two other recent avalanches in the area.