The links below will take you to pages with more detailed information on hurricane development and preparedness:
2015 Storm Surge MapClick for a larger map
HURRICANE PREPAREDNESS GUIDES
→ Hurricane Evacuation Guide
→ Storm Ready Community
*note: some files are large and may take a few moments to download - thanks for your patience!
What is a Hurricane
The term "hurricane" is a specific name for a strong "tropical cyclone". A tropical cyclone is the generic term for a low-pressure system over tropical waters with organized thunderstorm activity and defined wind circulation. Tropical cyclones with maximum sustained winds of less than 39 mph (34 kts) are called "tropical depressions". Once the tropical cyclone reaches winds of at least 39 mph, they are typically called a "tropical storm" and assigned a name. If winds reach 74 mph (64 kts) then they are called a hurricane.
How are Hurricanes different from Tornadoes?
While both tropical cyclones and tornadoes are atmospheric vortices, they have little in common. Tornadoes have diameters on the scale of feet and are produced from a single storm (i.e. a thunderstorm). A tropical cyclone, however, has a diameter on the scale of miles and is comprised of several to dozens of convective storms. Tornadoes are primarily an over-land phenomena as solar heating of the land surface usually contributes toward the development of the thunderstorm that spawns the vortex. In contrast, tropical cyclones are purely an oceanic phenomena - they die out over-land due to a loss of a moisture source. Lastly, tropical cyclones have a lifetime that is measured in days, while tornadoes typically last on the scale of minutes.
How does a Hurricane Form?
A hurricane needs several different factors present in order for it to develop.
1. Warm ocean waters of at least 80°F throughout a sufficient depth of at least 150 ft. Warm waters are necessary to fuel the heat engine of the tropical cyclone.
2. An atmosphere which cools fast as the elevation increases. This causes instability in the accumulation of moisture.
3. Relatively moist layers near the mid-troposphere (about 3 miles up). Dry mid levels are not conducive for allowing the continuing development of widespread thunderstorm activity.
4. A pre-existing near-surface disturbance with sufficient vorticity and convergence. Tropical cyclones cannot be generated spontaneously. To develop, they require a weakly organized system with sizable spin and low level inflow.
Having these conditions met is necessary, but not sufficient as many disturbances that appear to have favorable conditions do not develop.
What is a Hurricane Watch?
A hurricane watch is issued when there is a threat of hurricane conditions within 48 hours.
What to do during a Hurricane Watch
- Fill up your car with gas.
- Secure buildings.
- Review evacuation plan.
- Listen to a radio or television for official instructions.
- Check your family's emergency supplies.
- Bring in outdoor objects (i.e. toys, garden tools).
- Turn refrigerator and freezer to coldest settings.
- Secure outdoor objects which cannot be brought inside (i.e. boats, lawnmower).
- Store drinking water in clean bathtubs, jugs, bottles, and cooking utensils.
What is a Hurricane Warning?
A hurricane warning is issued when hurricane conditions (winds of 74 miles per hour or greater, or dangerously high water and rough seas) are expected in 36 hours or less.
What to do during a Hurricane Warning?
- Listen to a radio or television for official instructions.
- If in a mobile home, check tie downs and prepare to evacuate.
- Store valuables and personal papers in a waterproof container.
- Stay inside, away from windows, skylights, and glass doors.
- Keep a supply of flashlights and extra batteries handy.
- If power is lost, turn off major appliances to reduce power "surge" when electricity is restored.
If Evacuation is necessary
- Take blankets and sleeping bags to shelter.
- Tell someone outside of the storm area where you are going.
- Bring pre-assembled emergency supplies and warm protective clothing.
- Leave as soon as possible. Avoid flooded roads and watch for washed-out bridges.
- Lock up home and leave.
- More Evacuation Information
Adequate Disaster Supplies
- Flashlight and extra batteries
- Portable, battery-operated radio and extra batteries
- First aid kit and manual
- Emergency food and water
- Non-electric can opener
- Essential medicines
- Cash and credit cards
- Sturdy shoes
How to Protect your Home
Permanent shutters are the best protection. A lower-cost approach is to put up plywood panels. Use at least 1/2 inch plywood cut to fit each window. Remember to mark which board fits which window. Pre-drill holes every 18 inches for screws. Trim back dead or weak branches from trees. Check into flood insurance. You can find out about the National Flood Insurance Program through your local insurance agent or emergency management office. There is a 30-day waiting period before a new policy becomes effective. Homeowners policies generally do not cover damage from the flooding that accompanies a hurricane.
Developing your Family Emergency communications Plan
In case family members are separated from one another during a disaster (a real possibility during the day when adults are at work and children are at school), have a plan for getting back together. Ask an out-of-town relative or friend to serve as the "family contact." After a disaster, it's often easier to call long distance. Make sure everyone in the family knows the name, address, and phone number of the contact person.
- Help injured or trapped persons.
- Give first aid where appropriate.
- Do not move seriously injured persons. Call for help.
- Return home only after authorities advise that it is safe to do so.
- Inspect the outside of your home and surrounding area before attempting to enter. If you are unsure of the stability of the structure, DO NOT ENTER.
- Enter your home with caution.
- Avoid loose or dangling power lines and report them immediately
- Check refrigerated foods for spoilage.
- Use telephone only for emergency calls.
- Stay tuned to local radio for information.
- Open windows and doors to ventilate and dry your home.
- Beware of snakes, insects, and animals driven to higher ground by flood water.
- Take pictures of the damage, both to the house and its contents and for insurance claims.
- Drive only if absolutely necessary and avoid flooded roads and washed-out bridges.
Inspecting Utilities in a Damaged Home
Check for gas leaks--If you smell gas or hear blowing or hissing noise, open a window and quickly leave the building. Turn off the gas at the outside main valve if you can and call the gas company from a neighbor's home. If you turn off the gas for any reason, it must be turned back on by a professional.
Look for electrical system damage--If you see sparks or broken or frayed wires, or if you smell hot insulation, turn off the electricity at the main fuse box or circuit breaker. If you have to step in water to get to the fuse box or circuit breaker, call an electrician first for advice.