DVC has usually been very generous about points from reservations unable to be kept due to extreme weather conditions. Snowstorms, hurricanes and even severe thunderstorms at times have been accepted as reasons for cancelling/returning points in the past.
If you do have a circumstance come up where you need to cancel a reservation due to such conditions beyond your control, I'd suggest calling MS to explain and allow them to work some Disney magic. There may be times when they are unable/unwilling to return points, but it can't hurt to ask.
We have been at WDW for 4 hurricanes now - and I can't think of a safer place to be. WDW and the resorts have always been most generous keeping guests safe and comfortable even in the face of these situations. They have been most impressive !
