Looks like China Central Bank is about to clamp down on Bitcoin exchanges which explains BTC dump today: 
https://www.bloomberg.com/news/articles/2017-02-08/china-central-bank-said-to-call-bitcoin-exchanges-for-more-talks
https://www.bloomberg.com/news/articles/2017-02-08/china-central-bank-said-to-call-bitcoin-exchanges-for-more-talks