I'm not an expert in this, but if the flight operates, my biggest concern might be the subway system. It's an efficient way to get to/from DCA as well as around town. The weekend will be less of a problem, but if there is no subway on Monday, traffic could be a mess. When DCA has a rare snowstorm, it can mean waiting for hours in a taxi line, even if cabs are being shared. OTOH, taxi fare to most hotels is very reasonable and the ride is quick under normal conditions.

Before leaving home, check that your hotel is open for business, has power and water, and that there are functioning restaurants nearby at least.