any thoughts on this oneFollow

Saturday my computer decided to hold a gun to its head and pull the trigger. After 18+ hours of reloading everything I had I got to wow and let the updates run. After downloading an ungodly amount of updates it got to 690mb left. I had to then shut the computer down to impending doom from an approaching thunderstorm. I fired the computer back up after it passed and wow was back to having to download 9.8gb's again WTH. Any thoughts on why I have to keep re-downloading stuff I already downloaded? Any help/thoughts/ideas would be greatly appreciated.

It's also possible that it cleared it's cache when you closed it before it was done.