I am not using Coinbase to give you personal opinion but I have read multiple comments saying Coinbase is having some trouble with Ethereum at the moment so that may be it. it is either their node which is having some trouble or it may even be because they ran out of ethereum since everyone was buying it since the current pump is getting too big.
An exchange running out of something traded? I do not think that could be possible. If that happens then demand shoots up, and with no supply, the price of Ethereum will rocket possibly to 0.5 BTC/ETH.
They should suspend trading before that happens.
that may be. but that is not exactly how it will happen. because for the most part what we see on exchanges are virtual numbers, not real 1:1 coin. you see when you deposit your coins on an exchange they don't necessarily keep all the coins at hand to be able to pay right away if needs be. they do a lot of things with them to make more money and when the withdrawal requests exceeds the amount they keep ready they run out of coins to pay.
something similar to what banks do. if 1000 people deposit $1mil and then suddenly 900 of them want to withdraw the bank will run dry on 400th customer because they don't just put the $1mil in their safe to just hold for safekeeping.
but the orderbooks which are determining the price will still have "numbers" on them preventing the drastic changes in price.
and besides if price shoots up on one place, arbitrage will kick it down to normal and below levels.
