Just to add, I was at a University campus when the entire building's electrics went out and there was a significant pull due to relatively powerful computers in every room. They initially tried to bring the building back online altogether and failed. Then they tried to bring it back in sections and failed too. In the end they ended up going into each lab, turning every computer off at the wall to bring each lab's power back, and then turn each computer on one by one.
I can only imagine the difficulty of bringing large parts of the grid back online, that rush current must be immense.