Gallerist NY has an article and more pictures of the damage done by Hurricane Sandy, posted here, and headlined Chelsea Galleries Begin Recovery Work.
UPDATE: Here’s a Reuters story with different details.
I have not been south of 42nd St., and so have not personally seen the damage, but I have spoken to a couple of people, some on second floors or higher of Chelsea buildings who are assuming no damage but can’t gain access to see for sure. Those on the ground floor all seem to have suffered losses, even if they removed some art to storage on higher ground. From Gallerist, here’s a picture of Haunch of Venison Gallery on West 21st St.:
 