We were land-locked for 3 days when the 2013 flood occurred and we didn't even live close to water. Within an hour the town was cut into pieces. We are pretty prepared people but we always had an evacuation plan of being able to drive to a certain location. The flood changed that plan.
Here is Longmont:
Flooding was worse the 2nd and 3rd day as all the mountain water had to settle lower. We had enough food and water and didn't take water into the house, but it sure woke us up being stranded.