Not much is needed to see such a crash.
Just major exchange fraud e.g. BitFinex steal all the BTCs. Plus information that Theter is just currency which was created w/o any limits and it has no cover in any real US - basically its just scam. Then you will see waterfall like in 2014.
Indicators show that we are high now and correction move is very much needed. Obviously price will not drop suddenly to <1000$ levels even after very serious bad news.