Severe storms—known as hurricanes or Nor'easters—bring high winds and flooding. Winds combine with tides to cause storm surge, a huge wave that can push water miles inland. The storms also bring heavy precipitation that comes in bands. The bands can extend for hundreds of miles inland, causing widespread flooding. Slow-moving storms, such as Hurricane Irene in 2011, can travel into mountainous regions and produce especially heavy rain and significant flooding.

Learn more about hurricanes and tropical storms.

Hurricanes and tropical storms can result in heavy flooding. A storm becomes a named tropical storm when winds reach 39 mph, and it becomes a hurricane when winds reach 75 mph. However, even an unnamed storm can dump so much rain that flooding puts homes and businesses at risk in both coastal and riverside areas.

In addition, winds combine with tides to cause storm surge, a huge wave that can push water miles inland.

Learn more about hurricanes and tropical storms.

High winds and changing barometric pressures can result in storm surge that pushes floodwater up into bays, inlets, and creeks and across low-lying areas. Large, wind-driven waves can damage homes along the Great Lakes shorelines. The damage can be especially serious when the Great Lakes are experiencing a high water-level period.

Learn more about Great Lakes coastal flooding.

The West Coast also experiences serious storms, particularly during the winter rainy season. Storm systems such as a "Pineapple Express," or El Niño, paired with extreme high tides, can bring storm surge into tidal bays and creeks. Tsunamis, which create huge waves, pose further risk. As the tsunami wave barrels into the shore, its strong currents can cause immense damage to buildings in low-lying areas.

Learn more about the Winter Rainy Season.

The risk of coastal flooding has changed in recent years. FEMA is now conducting studies using the latest technology to analyze and map U.S. coastal flood risks.

Learn more about the new coastal maps.