Couple of riders took a stab at the bottom of the slope. Second rider went slightly higher than the first and the slope collapsed and fractured 200 feet above him. He was able to out run the slide before it came near him.
This demonstrates exactly what kind of conditions you will encounter out there right now. You might not see many obvious signs of instability until you tickle the right slope. The early season snow should not be trusted right now. It remains weak and after the large recent storm, it is still prone to collapsing and causing dangerous avalanches.
After the avalanche, the group encountered a number of other significant collapses while traveling in the afternoon. Collapsing is one of the major signs of avalanche danger.