In the spectrum of severe weather disasters, flooding may be the most commonplace. Flooding can not only affect communities directly receiving precipitation, but also communities downstream from a severe weather event, sometimes days or weeks after the original storm. Because of this, flooding is a risk to residents almost anywhere.
Not all flooding threats are the same, and they can occur in different seasons. During the late winter and early spring, a flood event may occur once snow and ice from the winter season begins to thaw and approaches the communities downstream from where the precipitation occurred. Because the ground is hard and frozen, water cannot penetrate it and be reabsorbed. When snow and ice melt, water runs off the surface and flows into lakes, streams and rivers, causing water to spill over the banks.
The types of most common flooding vary with the region – the Northeast face remnants of tropical disturbances in the summer, but are also threatened by winter flooding, nor’easters and the threat of rapid spring melts. The Midwest experiences major river flooding over vast stretches of low-elevation land. The West Coast’s intense flooding season typically spans November through March and results in millions of dollars in damage for residents each year.
The risk to a particular community depends on several factors. Those in low-lying areas surrounded by areas of higher elevation are consistently at risk for spring thaw flooding, especially if the surrounding high areas encounter heavy snowfall during the winter season. Other factors affecting the degree of flood threat are whether the soil has high moisture conditions prior to snowfall, if rain falls heavily during the melting period, if snow melts rapidly or if ice jams have formed in rivers over the winter.
The National Oceanic and Atmospheric Administration’s National Weather Service (NWS) has a warning scale intended to alert residents to flood risks. This system is used during weather events that bring large amounts of precipitation in a short period of time.
- Flood Watch: Flooding is possible. Tune in to NOAA Weather Radio, commercial radio, or television for information.
- Flash Flood Watch: Flash flooding is possible. Be prepared to move to higher ground; listen to NOAA Weather Radio, commercial radio, or television for information.
- Flood Warning: Flooding is occurring or will occur soon; if advised to evacuate, do so immediately.
- Flash Flood Warning: A flash flood is occurring; seek higher ground on foot immediately.
The National Weather Service monitors the flood risk of rivers across the United States, which can help residents identify if their region is experiencing heightened flood risks.
Flooding often occurs rapidly, so one year-round safety measure that residents can follow is housing important documents in a waterproof container that can be carried from the home on short notice. Sometimes, the best defense against flooding is guaranteeing a structure is insured against flood damage, above and beyond any homeowners insurance coverage.
Keeping a home protected requires homeowners to take certain steps. Residents in high flood risk areas should make sure to elevate their furnace, water heater and electrical panel. Plan to install “check valves” to prevent flood water from backing up into drains. Seal walls in basements with waterproofing compounds as well as possible. Most importantly, store non-perishable foods in an elevated space to prevent contamination from flooding.
Find additional information on how to plan and prepare for floods, what to do during and after a flood and learn about available resources by visiting the following: