Hurricane safety, explained | National Oceanic and Atmospheric Administration

Slow-moving storms, like Hurricane Florence (2018), Hurricane Harvey (2017) and Tropical Storm Allison (2001), can dump an enormous amount of rain on one area — on rare occasions 30 or more inches over the course of one storm. Always listen to local emergency managers and follow evacuation orders when issued. 

Any body of water — a lake, river, stream, or pond, including ones that are far inland — is at risk of flooding during a hurricane or tropical storm. The ground may already be saturated with water if there has been heavy rains before the hurricane, meaning an even higher likelihood of flooding. In general, if you are on flat ground and you can see a body of water during a hurricane, you are too close to it. If you live in an area prone to flooding, you may need to evacuate — this may be only a few miles or quite far, depending on the local conditions. The purpose of an evacuation order is to get you safely to a place that is at low risk of flooding. 

Flooding can still be a major hazard weeks after a hurricane passes, even when evacuation orders may have expired and wind is no longer a threat. This can be especially true in areas near rivers that are downstream from where hurricanes make landfall. Dams must release the excess water from hurricane rains, which can result in flooded downstream rivers with strong and dangerous currents weeks after a hurricane. In mountainous areas, especially in the Caribbean and Central America, but also along the Appalachian range, heavy rainfall can lead to land and mudslides.