I am not an expert, so take my views with a grain of salt.

I think there are several reasons for it... Well, maybe none of these reasons seem that bad/troublesome but when all of them are put together in a span of one week... traders get scared.

1. Ethereum flash crash
2. Ethereum's scaling issues that were so clearly visible during ICOs
3. ICO schemes controlling a lot of Ether
4. Bitcoin's potential upcoming fork (again, potential)

There are just way too many reasons for uninformed traders to quit the market, but these are just my thoughts on it.

But the way I see it... Bears make money, Bulls make money, Pigs get slaughtered. I had bought 70% of my portfolio before the crash but I am looking I am buying the remaining 30% now lol. I wish I could have bought 100% of portfolio right now! xD

But there is blood on the street and there may just be a lot of blood for a while... HODLLLLLLL and believe in the tech! I am sure cryptocurrencies someday will be as common as credit cards and every penny you're investing will pay back! :)