A hurricane is a tropical cyclone with sustained winds of at least 74 mph. Hurricanes are categorized based on the Saffir-Simpson Hurricane Wind Scale, which is a 1 to 5 rating based on a hurricane's sustained wind speed. This scale estimates potential property damage.
The primary hazards associated with hurricanes are:
Storm surge is an abnormal rise of water generated by a storm (such as a tropical storm or hurricane), over and above the predicted astronomical tides. Storm surge is generally created by the strong winds associated with a tropical storm or hurricane.
During a tropical storm or hurricane, storm surge may pose the greatest threat to life and property. The destructive power of storm surge and large battering waves can destroy buildings, create beach and dune erosion, damage roads and bridges, and cause loss of life. Tropical storms, all categories of hurricanes, and post-tropical cyclones can all cause life-threatening storm surge.
Know Your Zone - ocean water associated with storm surge may quickly cause flooding and damage property along the coastline and miles inland. Areas that may be flooded or damaged during tropical storms and hurricanes have been designated as Hurricane Evacuation Zones . Be prepared - - know whether you live or work in a Hurricane Evacuation Zone. Use the interactive Hurricane Evacuation Zone Map to learn whether you live or work in a Hurricane Evacuation Zone.
More Storm Surge Resources:
- NOAA's Storm Surge Can Be Deadly brochure .
- NOAA's Introduction to Storm Surge Guide
Tropical cyclones and hurricanes often produce widespread, torrential rains in excess of 6 inches, which may result in deadly and destructive flooding. In fact, flooding is the major threat from tropical cyclones for people living inland. Hurricane Diane in 1955, Westfield, MA (which is approximately 90 miles from the coast) received nearly 20 inches of rain. During Tropical Storm Irene in 2011, areas of western Massachusetts received over 7 inches of rain.
Flash flooding, defined as a rapid rise in water levels, can occur quickly due to intense rainfall. Longer term flooding on rivers and streams can persist for several days after the storm.
Rainfall amounts are not directly related to the strength of tropical cyclones but rather to the speed and size of the storm, as well as the geography of the area. Slower moving and larger storms produce more rainfall.
Hurricane‐force winds (defined as winds that are at least 74 mph) are extremely dangerous: they can damage or destroy buildings and mobile homes and they can turn loose items such as signs, roofing material, siding and lawn furniture into dangerous windborne projectiles.
Hurricanes are classified into five categories according to the Saffir-Simpson Hurricane Wind Scale, which estimates potential property damage according to the hurricane's sustained wind speed. While the Saffir-Simpson Hurricane Wind Scale categorization includes wind speeds, it does not include other major hazards such as storm surge and rainfall which can also be destructive and deadly.
|Saffir-Simpson Hurricane Wind Scale|
|Category||Sustained Winds||Types of Damage Due to Hurricane Winds|
|Very dangerous winds will produce some damage: Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.|
|Extremely dangerous winds will cause extensive damage: Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.|
|Devastating damage will occur: Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.|
|Catastrophic damage will occur: Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.|
|157 mph or higher|
137 kt or higher
252 km/h or higher
|Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.|
Hurricanes and tropical storms can also produce tornadoes. These tornadoes most often occur in thunderstorms embedded in rain bands well away from the center of the hurricane; however, they can also occur near the eyewall. Usually, tornadoes produced by tropical cyclones are relatively weak and short-lived, but they still pose a significant threat. Learn more about tornado safety and preparedness on our Tornadoes webpage.
The strong winds of a tropical cyclone can cause dangerous waves that pose a significant hazard to mariners and coastal residents and visitors. When the waves break along the coast, they can produce deadly rip currents - even at large distances from the storm.
Rip currents are channeled currents of water flowing away from shore, usually extending past the line of breaking waves, that can pull even the strongest swimmers away from shore. Find out more about rip currents on the NWS Rip Current Safety page.