What time of day did the large slide occur?
As far as I am aware, there were no injuries resulting in a request for SAR personnel.
I don't know who was leading the groups in question or the trip as a whole, and I'm not going to second-guess anyone without hearing the full story, but I am sure that this "close call" will be investigated and taken seriously.
Mountaineers avalanche training is a work in progress. Right now, all Intermediate Climbing students, Winter/Advanced Scramble students, and Backcountry Ski students need to take an Avy Level I to graduate. The Mountaineers offer an Avy L1, with instructors from its own ranks. These instructors have been through additional outside training by the Crystal Mountain staff.
At some point, we'd like all leaders to have an Avy L1, but there's the problem of grandfathering in folks / giving a grace period so we don't lose leaders.
All basic students receive about an hour's worth of lecture and videos and are told to be assertive and ask questions / raise concerns if something seems amiss.