Storm surge is the most common killer in a hurricane and causes more damage than any other force in a hurricane. Nine out of ten deaths from a hurricane can be attributed to storm surge. Excessive winds near the storm center, while the storm is still over open waters, generate a rise in sea level. This rise in water is pushed ahead of the storm, and can strike the coast before the storm even makes landfall. The storm surge is usually a gradual rise in the sea level and can start when the storm is as far away as 500 miles.

As the storm approaches land, the storm surge continues to increase in height. Storm surge reaches the maximum height at nearly the same time that the eye of the hurricane makes landfall. The height of the storm surge is dependent on a number of parameters, including the bathymetry of the offshore waters (water depth), wind speed, storm speed and storm heading. Assuming that all other variables were the same, a storm surge in Texas would be less than a storm surge on the Mississippi coast, where the depth of the water offshore is quite shallow. See Figure 12.

In general, the storm surge is worst just along the coast. However, the storm surge can produce abnormally high tides in bays, due to channeling and tipping caused by the wind. The low barometric pressure in the eye of the storm can raise water level a foot for every inch the pressure drops.