Excessive wind on large bodies of water like the Bay or large lakes can be dangerous as well. It is typically more an annoyance while running whitewater. Severe wind can topple trees and large limbs into waterways and along access roads. I pack a small Gerber saw in my pin kit exactly for this scenario and have used it on several river trips.
Besides large rivers like the Potomac, really strong winds blowing upstream can make controlling your boat in rapids a bit challenging. Instead of worrying about just currents, rocks, etc. - you now have a third dimension to deal with. Besides larger waves, strong upstream winds may blow your boat off line. This is not unusual for canoes since they have such a large wind profile. Here is a good article on paddling in high winds for kayakers: Kayaking in High Winds. This is another good article from the ACA: Wind, Waves, Current.