This is the greatest hurricane threat to life and property, and it can be devastating. Storm surge is a large dome of water often 50 to 100 miles wide that sweeps across the coastline near where a hurricane makes landfall. The stronger the hurricane and the shallower the offshore water, the higher the storm surge will be.
The storm tide is the combination of the storm surge and the normal astronomical tide. For example, a normal tide of 2 feet added to a 12 foot storm surge results in a 14 foot storm tide. The "worst-case scenario" for an approaching hurricane is for the storm surge to arrive around high astronomical tide. This mound of water, topped by battering waves, moves ashore along an area of the coastline as much as 100 miles wide. The combination of storm surge, battering waves, and high winds can be devastating and deadly.
Winds and Squalls
A squall is a significant increase in the average or sustained wind speed which will usually be observed with a convective line of showers and thunderstorms. Hurricane force winds can destroy poorly constructed buildings and mobile homes. Debris, such as roofing material, traffic signs, aluminum siding, and small outdoor items can become flying missiles. Remember, a hurricane with winds of 150 mph has four times the energy of a hurricane with winds of 75 mph.
Heavy Rain and Flooding
Heavy rain and flooding is a threat to inland areas as well as coastal communities. Rainfall in excess of 6 inches is likely in many hurricanes, and can produce deadly and devastating floods.
These tornadoes most often occur in thunderstorms embedded in rain bands well away from the center of the hurricane, but can also occur just outside the center of the hurricane.