Cadwallader range Avalanche

Remotely triggered class 3 avalanche on a NW aspect at 2100m. we were a party of 4 that descended into the bowl. On our way out the bowl the last person got caught from the release high above and off to the side. Seven sled tracks travelled before it released. Started in the steep shallower snowpack and then stepped down to suspected early march weak layer and propagated across the slope in both directions. One person and sled partially buried. We were aware of the hazard high above and off to the side and spaced ourselves well apart. We believe this to be remotely triggered as there was movement from the other sledders on the other side of the ridge opposite the start zone. the run out zone or toe of the debris is unknown as we were not in position to see the bottom. The debris turned the corner apprx. 150-200m away.