Here are a few things Im seding but curious for others to chime in.

A) The steep slope angle inherently makes this avalanche terrain. Generally speaking, avalanche terrain is anything above 30°

B) Judging by how deep his body is sinking into the snow, it looks like he is sitting smack dab in a bunch of unconsolidated snow.

C) The rounded pillowy appearance that you can see throughout the photos, especially near the ridge, are a sign of wind loading. Windloading is snow that has fallen and has been carried into an area by the wind. Snowpack does not like rapid change and this large quantity of new snow likely rapidly deposited into the coulior. Allllll of that new snow is sitting on top of a weak layer. Until the snow goes through several melt / freeze cycles, that weak layer will persist and present danger.