It looks a bit like snow, but it is foam from some kind of fire extinguisher.
There was a 3 alarm house fire at one of the houses on the lake, just a block from where I work.
The garage exploded and burned the house, then... to add insult to injury, the car that wasn't in
the garage caught on fire from the falling debris.
The owners were safely outside. Elderly people who were very shaken and upset.
The firemen were working on this house fire for the entire afternoon.