Chick one is fine, chick two appears to have passed away at this point.
And no, it wasn't a question of weather, the box is high and dry, so no need to worry about the surviving chick, s/he looks great, active and strong and getting fed well.
As for the chick that died, that it survived to hatch at all was a long shot, but Nature doesn't play the odds. Usually those kind of small miracles are a great thing. Not in this case I'm afraid. And no, there was nothing that could be done.