The second was caught and carried 300 ft down the slope. He self arrested with verts and his poles and was on top of the snow uninjured when he came to a stop. HS-ASr-U-R2-D1.5-O
The slide took place as party of 3 was ascending the Memorial #1 couloir on the backside of Mt. Olympus. As the first of the group reached the top of the couloir and the second person stepped out onto the slope, the slope collapsed with two people on it. The second was caught and carried 300 ft down the slope. He self arrested with verts and his poles and was on top of the snow uninjured when he came to a stop. HS-ASr-U-R2-D1.5-O
Lessons: We were at a lower elevation and in one of the outlying areas where the PWL is more present... The snow in the couloir felt stable on the ascent. As we approached the final roll to the top we did not re-group to discuss continuing. It was cold and shady in the couloir and the top looked like great views, sunny and warm. I have skied the couloir in the past and knew that the top always has the convex roll over from wind loading. I was tricked because the stubborn hard slab was capped with 6-8 inches of fresh snow on top. Although it was convex and in retrospect was obviously wind loaded it did not feel slabby on top and the verts were punching through the new snow and it felt supportable. It did not seem like the same persistent slab that slid was present futher than 15 or 20 feet down the couloir. We felt that the heavy windloading at the convex roll was what activated the layer. As soon as the second stepped onto the slope with the first on top of the slab, the increased load was enough to cause a collapse and take the second for a ride.
Looking at the convex roll we should have skied from just below it and not have tried to push for the top of the couloir. Looking back, it was obviously wind loaded. The stoke was high as we could see the sun and the phenomenal powder. We should have SLOWED DOWN and better communicated our concerns. I'm glad my partner(s) are okay.