i know of a family from out of town that made 2 chasunas within 10 months, each one during a major weather “event” in NY. The first was during the major snowstorm at the end of 2010, when the city didn’t get plowed for days. That chasuna had to be postponed until the next night, because the chosson and kallah were in different boroughs and couldn’t get to each other. The poseik had said that if the kallah wouldn’t have friends at the chasuna, it should be postponed. By the way, the GO of the local Bais Yaakov (or whatever high school it was)called the caterer to find out of there was a simcha in the hall that night, and it there were people there, because if there weren’t, she could round up the entire student body to come and dance for the kallah! Mi K’Amcha Yisroel!
This families next chasuna fell out on the day the Hurricane Irene struck. B”H it was not postponed, though many catering halls on the Island had to cancel their affairs on that Sunday. Many people were not able to come because the hurricane hit different areas at different times, but those who were there made it a beautiful, leibadik event.
We should do what we can to keep the dates of the wedding, but it is certainly not worth endangering anyone’s safety.