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Hurricane Season Terms & Acronyms

Familiarize yourself with the terms that are used to identify a hurricane.

  • A hurricane watch or tropical storm watch means a hurricane or a tropical storm threat to the area is possible within the next 48 hours. Be prepared to evacuate, as even a tropical storm can gain strength quickly and many homes, including mobile homes, reside in high risk areas. Monitor local radio and television news outlets or listen to NOAA Weather Radio for the latest developments.

  • A hurricane warning or tropical storm warning is issued when a hurricane or tropical storm is expected in the area within the next 36 hours. If local authorities advise you to evacuate, you need to leave immediately.

  • Hurricanes are classified according to the Saffir-Simpson Wind Scale into five categories based on their wind speed, central pressure, and damage potential. Category Three and higher storms are considered major hurricanes. While less intense, Category One and Two hurricanes and tropical storms are still extremely dangerous and warrant your full attention.

  • Storm Surge is an abnormal rise in sea level accompanying a hurricane or other intense storm. As a hurricane makes landfall, this storm surge is pushed onshore, causing severe flooding and destruction. The waves of the surge can undermine waterfront structures, wash out roadbeds, destroy ships, and cause drowning. Storm Surge forecasts are included in hurricane and tropical storm advisories and statements issued by the National Weather Service, but arbitrary levels are no longer assigned to each category. Storm Surge is instead now calculated for each storm, taking into account variables such as tide, storm size and rain amounts, and should be much more accurate and reliable.
Saffir-Simpson Wind Scale
Sustained Winds
Types of Damage Due to Hurricane Winds
Tropical Depression
Tropical Storm
One (1)
74-95 mph
64-82 kt
119-153 km/h
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.
Two (2)
96-110 mph
83-95 kt
154-177 km/h
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.
Three (3)
111-129 mph
96-112 kt
178-208 km/h
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.
Four (4)
130-156 mph
113-136 kt
209-251 km/h
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.
Five (5)
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.
  • A tropical storm has all the characteristics of a hurricane, including storm surge, with winds of 39 to 73 mph.

  • Hurricanes frequently produce widespread torrential rains with floods. Deadly and destructive flooding and flash flooding can result from these rains. Slow moving storms tend to produce especially heavy rain. Flooding in creeks, drainage channels, rivers and streams may persist for several days or more after the storm.

  • Emergency Management: Organized analysis, planning, decision making, and assignment of available resources to mitigate, prepare for, respond to, and recover from the effects of all hazards.

  • Emergency Operations Center (EOC): A pre-designated facility established by an agency or jurisdiction to coordinate the overall agency or jurisdictional response and support to an agency.

  • The Governor of South Carolina may authorize a voluntary evacuation or require a mandatory evacuation. You are encouraged to evacuate when instructed. Evacuations of specific areas occur when authorities determine that there is an immediate threat to your life and safety. Please review the Citizen's Guide to Emergency Preparedness for emergency supplies and other information that you should have on hand for evacuation. PREPARE NOW. Know where you will go if evacuated. Anticipate that roads on and off the Island will be congested and difficult to maneuver. Leave early if possible.

  • Federal Emergency Management Agency (FEMAExternal Link Icon): The Federal agency created in 1979 to provide a single point of accountability for Federal activities related to disaster mitigation and emergency preparedness, response, and recovery.

  • Flash Flood: A flood that crests in a short period of time and is often characterized by high velocity flow. It is often the result of heavy rainfall in a localized area.

  • Flash Flood Watch: A flash flood is possible in the area; stay alert.

  • Flash Flood Warning: A flash flood is imminent; take immediate action.

  • Gale Force Winds: Winds with a speed from 32 to 63 mph.

  • Hazard Mitigation: Actions taken to prevent disasters or to reduce the damage caused by hazards that cannot be avoided.

  • High Wind Warning: Sustained winds of 40 mph or greater, or winds gusting to 58 mph or greater which are either expected or observed regardless of duration. Will be issued for inland areas, away from the coast, where hurricane force conditions are not expected.

  • Huricane Season: Begins June 1st and ends November 30th. Most active time in the Atlantic Ocean is in August and September.

  • Re-entry and Recovery: After the disaster has occurred, the Town will issue an all clear bulletin to all participating agencies and announce times when reentry into evacuated areas may begin.

  • Small Craft Cautionary Statements: When a tropical cyclone threatens a coastal area, small craft operators are advised to remain in port or not to venture into open sea.