Wow, the Volt must be so quiet the freight train didn't hear it coming. I just hope the car was unoccupied when it rolled off a cliff.
If the battery pack is still somewhere amongst the twisted metal, I'd bet most of the cells survived the blow. It could probably be rebuilt unless there was short that damaged all of the cells.
Granted you may get a steal on the pack, then you got to get a bms and charger. Ive seen deals on various ev sites, ebay and group buys. Just got to keep searching.