And the backup before that? Or older ones? What's the newest backup that will restore (hint, the last time your scheduled checkDB ran successfully should be a hint. You do have scheduled integrity checks, right?)

Looks like the flash drive has failed. It does happen. Was it not in a RAID array? That would at least save the data long enough to get it somewhere else.

Can you post the latest SQL error log? There may be entries in there that suggest when the problems started.