As we were wrapping up our tour to Room of Doom we decided to try to gain a little elevation on the exit and drop into Mongo No on our way out. We didn't know the terrain here well. The wind had been swirling the entire time we were in mineral basin. The snow was soft and great in Doom but as we gained elevation to drop into Mongo No we noticed the snow becoming dense and wind loaded. But nobody in our party of 3 said anything about it out loud. We intuitively slowed down and spread out but didn't otherwise discuss it. We transitioned and decided to stay more on the Santiago (east facing) side since we couldn't see into Mongo No very well. The first member of our party descended Santiago (east facing) then cut over to the ridge between the two lines about half way down. We radioed him when he got there to see what he thought. He said there were some rocks but he could see a way through. I (skier 2) radioed back that I was going to drop straight down Santiago and come in under the rocks instead. As I reached the bottom of the line skier 3 radioed, from our transition spot, asking skier 1 how he was. Skier 1 replied that he had just been in an avalanche. I hurried around under the rocks and could then see the avy path and skier 1 standing in the middle of it. I skied along the low angle edge of the path to him where he said he was ok. Skier 3 arrived shortly after via the same line as skier 2. Skier 1: "We were nearly done and were skiing down Santiago. I went first and sort of meandered off the open slope and radioed that I was going to slide into a little (very little) gully. One turn and I'd be out in the open. But the second I touched the gully the entire slope just started moving, and fast. I've been carried but never at that speed." It was enough snow that he was going under and getting snow into his mouth. Both skis broke. He lost his poles, headlamp and glasses as well. He skied out on a single ski with a broken tail.

An observer skinning up observed the entire thing. He said at first skier 1 was on top but quickly disappeared under the snow. The observer tried to pay attention to the last known spot of skier 1. The observer thought for sure he was going to be digging skier 1 out and started sprinting up the skin track but then said he saw skier 1 pop out.

Avalanche specs:

Slope was wind loaded. It broke 30-40 feet across and propagated out. The crown did not look big at all from below. We did not measure it. Toe of the avalanche was probably 2 feet high? Ran a couple hundred feet. We saw another avalanche on a similar aspect as we exited Mineral as well.

Mistakes:

1. We should have verbally discussed the change in snow conditions and the amount of wind. We all got nervous but nobody said anything.

2. We should have kept eyes on each other. Had he not popped out and had a third party not seen it from below we would have had to scan the entire path for him since we never had a visual on his last known spot. That would have cost us precious time had we needed to dig him out.