The ETH network has been unable to process the transactions timely and too many ICOs pricing in Ethereum . Those ICO recipients won't hold everything in ETH, if it isn't a stable store of value. This is undoubtedly part of the downward pressure on ETHUSD price. This liquidity issue will be bad and hurt ETH, it may help BTC , unless they hurt themselves by messing up the SegWit2x/UASF/BIP148/Miner-Vs-Ecosystem conflicts.
Diversify your holdings of Digital Assets is my recommendation if you are a HODLer or long term investor. If you are a Trader, welcome to truly "Free Markets". You are on your own. And IMO , no, Stops will not Protect you. It might have been Sell Stops that CRaShEd ETH down to $13, because CoinBase and the ETH Network couldn't keep up with the of transactions.
Edit to add news article link: Here is one article link: http://www.coindesk.com/13-ethereum-ether-prices-plunge-2500-gdax-exchange-flash-crash/
In this article is a link to a Reddit post:
BY: emansipater 170 points 7 hours ago
"I assume that (unlike all the price discussion here which is totally offtopic) you are referring to the transaction issues which have led several exchanges to pause ETH withdrawals. Here is what happened:
The badly designed Status ICO clogged up the network yesterday with a huge number of high gas fee transactions, most of which are failing but still filling up the blocks and preventing normal tx's from getting in.
In addition, dwarfpool and perhaps others have set bad defaults on their client software that both actually cost themselves money and also prevent the network from automatically adapting to larger gas volumes the way it's supposed to.
Furthermore, evidence is accumulating that f2pool was actively manipulating transactions bound for the Status ICO, which they participated in themselves, exacerbating the problem. Experts explained weeks ago that bad ICO designs are vulnerable to such attacks, but this appears to be the first time it was actually executed in the wild.
So now, even though the Status ICO is over, there are still a huge number of transactions clogging up the network and the only way to get transactions in is to pay huge fees (which most of the exchanges probably don't want to do). Until it clears out, people are going to be missing ENS auctions, unable to withdraw from many wallets and exchanges, etc. etc. etc.
TL;DR: badly designed ICOs, plus selfish and foolish miners = major delays and maybe even substantial losses for everyone else."