US stock markets will be closed Monday and possibly Tuesday in the face of Hurricane Sandy. Hurricane Sandy is currently a category 1 "megastorm" putting 50 million people at risk along the East Coast. NYC is in the path which is why the markets will be closed.
Natural disasters are sometimes golden buying opportunities. Average investors are prone to panic at any hint of bad news, I wouldn't be surprised to see stock markets opening lower when trading resumes. Natural disasters happen from time to time, it's normal. Barring cataclysmic events, hurricanes don't concern me (although I hope nobody gets hurt). I've made it through two typhoons here in Korea this year.
I'll be monitoring news the next couple days and will put in a couple limit orders in case Mr. Market overreacts.
Edit 10/31/2012: I deleted a statement I made the other day because this hurricane turned out to be worse than I originally thought. I've been through category 1 typhoons (same thing as hurricane, just depends on the ocean) this year and while it's not exactly fun I never felt truly threatened. They had me stay at work through one of them to supervise soldiers, and monitor the equipment as well as wind speeds. There are procedures I have to follow depending on wind. I witnessed trees snapping and debris all over the road the next day. Roads were closed and we were stuck up there on top of a mountain. Not fun. I didn't have to deal with flooding or my posessions being ruined.
I don't want more natural disasters to occur, but I hope that I'll be sent to help clean up if it happens in the future. I really hope to get a humanitarian mission like that sometime. I know soldiers who were ordered to go help Haiti, I want to do something equally as awesome!