Then those balances will be stuck overnight if no one can't access it. The market will become frozen for the meanwhile but when it's able again, you must not be surprised with the possible panic selling because of that incident.
Many will start to decide to sell their crypto assets before it vanish completely. This is a kind of scenario that will only happen if the world's internet will be totally shutdown but it's unlikely to be seen, thanks to the great tech behind bitcoin.
There are some scenarios how crypto-currencies can disappear, we can see them in some topics here on forum.
Different types of disasters are mentioned, for me one thing is sure, if it comes to some bad scenario, coins will be
the last thing on our mind, we will think how to survive! We can't eat and breath internet and coins we have on the
internet.
I'm not one of the people who see end of the world and prophecy disasters as possible in some near future.