Tropical Cyclones


A tropical cyclone is a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has a closed low-level circulation. Tropical cyclones rotate counterclockwise in the Northern Hemisphere. They are classified as follows:

  • Tropical Depression: A tropical cyclone with maximum sustained winds of 38 mph (33 knots) or less.
  • Tropical Storm: A tropical cyclone with maximum sustained winds of 39 to 73 mph (34 to 63 knots).
  • Hurricane: A tropical cyclone with maximum sustained winds of 74 mph (64 knots) or higher. In the western North Pacific, hurricanes are called typhoons; similar storms in the Indian Ocean and South Pacific Ocean are called cyclones.
  • Major Hurricane: A tropical cyclone with maximum sustained winds of 111 mph (96 knots) or higher, corresponding to a Category 3, 4 or 5 on the Saffir-Simpson Hurricane Wind Scale.

North Carolina is especially vulnerable to direct tropical cyclone strikes because the coastline extends out into the ocean. Heavy winds, tornadoes, flooding, and storm surges can all be caused by hurricanes, causing billions of dollars in damage.

All tropical cyclones should be taken very seriously regardless of the category. Although categories of hurricanes are determined by wind speed, most damage occurs from flooding so wind speed alone does not determine the severity of a storm. Hurricane Florence, which made landfall in Wrightsville Beach in 2018 as a category one hurricane, caused $24 billion in damages; more than the cost of Hurricane Matthew (2016) and Hurricane Floyd (1999) combined.

If New Hanover County's Emergency Operations Center (EOC) is activated due to a hurricane or other emergency event, emergency information and instructions will be provided.

ReadyNHC: Make a Plan, Build a Kit, Stay Informed

The cone represents the probable track of the center of a tropical cyclone, and is formed by enclosing the area swept out by a set of circles along the forecast track (at 12, 24, 36 hours, etc). It assesses the official forecast errors over the previous 5 Example of the 5-day cone with the wind fieldyears and notes where 2/3 of those errors fell. This means that 2/3 of the time (60%-70%), the storm should stay within the area of the cone...ANYWHERE within the area of the cone.  But, it also means that 1/3 of the time, the storm could move outside of the left side of the cone or the right side of the cone.  

In our example of the anticipated track of Hurricane Laura:

  • The dots in the middle of the cone represent the strength of the storm and when the storm might reach that strength at that point in the forecast.  It does NOT pinpoint the center of the storm or indicate the exact track of the storm.
  • The center of the storm could be ANYWHERE in the white portion of the cone.  60% to 70% of the time, the center of the storm will stay in that general area of the cone. 
  • One-third of the time, the storm could be to the left or to the right of the cone.
  • In all instances, impacts of the storm can be felt WELL outside of the cone all together.
  • You should use the cone as an awareness tool.  When you see that a storm might impact your region, you should, at a minimum, review your plans and check your emergency kits.  If the storm moves and does not impact you, you'll know your resources are ready; if it does hit you, you'll be ready to go and protect you and your family.

DO NOT USE THE CONE ALONE, OR THE LINE IN THE MIDDLE OF THE CONE, AS AN INDICATOR TO WHERE DAMAGE WILL BE LIMITED TO DURING A STORM.


Screenshot for NHC


It is important to note that winds, rain, storm surge, and damage can occur WELL outside of the white part of the cone.  Check out this video for info from the National Hurricane Center on how to use this information to help keep your family safe during the next storm. 

Most importantly, you need to know what your local hazards are. Find out if you live in an evacuation zone so you are ready to follow evacuation orders. Learn whether storm surge is a risk in your area (even if you are inland). 

Develop an Evacuation Plan

If you live in an evacuation zone, determine how you will evacuate and where you will go if an evacuation order is issued. How will you get to your destination? Be sure to plan an alternate route! How can you take care of your pets? You don’t necessarily need to travel hundreds of miles to be safe, but always make sure your evacuation destination provides protection from hurricane hazards, like inland flooding near a river, creek, or dam or mudslides. 

Assemble Disaster Supplies

Devastating hurricanes can lead to long recovery times. Be prepared with at least three days of supplies (or more!) including water, non-perishable food, medicine, and pet supplies. Extra cash, a battery-powered radio, flashlights, and a portable crank or solar powered USB charger to charge your cell phone are also important. These supplies are helpful in any disaster, not just a hurricane, so it is always a good idea to have them on hand.

Get an Insurance Checkup

Check with your insurance agency before hurricane season to learn what is covered. Homeowners insurance does not cover flooding. Flood insurance requires a separate policy for both owners and renters and it takes 30 days to kick in. Learn more about the National Flood Insurance Program. 

Strengthen Your Home

You can take steps to make your home more resilient to threats from a hurricane. Purchase plywood, steel, or aluminum panels to board up windows and doors and have them on hand. Keep your trees trimmed. Secure loose outdoor items and furniture and find a safe place for your car. 

Help Your Neighbor

Get to know your neighbors and their needs. Many people, especially senior citizens, may need help from neighbors before, during, and after hurricanes.

Once you have made all of these preparations, write them down! It’s easy to forget something you planned far in advance. Store your written plan somewhere safe, have photo documentation of valuables, and share your plan with your family. 

Determine your risk Develop an evacuation plan with alternate routesAssemble your supplies to include food, water, and resources
Make sure you have the right and adequate insuranceRepair and maintain your homeMeet and help your neighbors if needed

Write your plans down to share with family and others