Thanks for all of the advice above. I called regarding a reservation for tonight. Evidently they are getting a lot of calls, as I waited on hold for about 10 minutes to speak with someone. After verifying that there is in fact a blizzard in DC right now, they were able to cancel my reservation that starts tonight. Keep in mind that all they can do is cancel your reservation and refund your money. They can not change a reservation to cut off the first night(s). Fortunately, there were still inexpensive rooms where I'm headed, so I made a new reservation for fewer nights at the same property.