I think people are tired of HEATING their houses during the summer, mine X11 and save power in 2 ways, less to power the cards and less AC needed.
Surely happens, but not THAT fast, it's more a continuous process.
The POW phase of XC ended last night and it was 10x more profitable then mining DRK at that moment. Now the XC price has tripled since then.
If you want paranoia look at the XC hashrate graph.
http://liteshack.com/?coin=xcGood point, I didn't know about XC. Doesn't explain doubling the hash-rate completely, but helps to understand it.
And thanks for the link!