How to understand Hurricane Alerts or Warnings

Understanding hurricane watches or warnings is critical to staying safe. During this period you should prepare your home and review your evacuation plan in case the storm hits the indicated area.


Whenever a hurricane or subtropical storm forms in the Atlantic, the National Oceanic and Atmospheric Administration (NOAA) issues advisory reports at least every 6 hours: at 5 a.m., 11 a.m., 5 p.m. and 11 p.m. EDT.


Pay close attention to hurricane watches or warnings and instructions from official authorities in your area.

What is an evacuation order


If your area has a mandatory evacuation order , it means you need to get out of your house and get to a safe place as soon as possible.

When a storm approaches, local officials will determine which areas and residents are most at risk and should evacuate. The highest risk areas in Zone A will be evacuated first, followed by Zone B, and so on. A staggered system will be used to help reduce traffic.


During a disaster not all areas will be evacuated. Emergency managers will work with the media to notify residents and visitors of affected areas and evacuation instructions.


Local officials are responsible for ordering evacuations. Pay attention to hurricane watches or warnings. The media in your area to stay up to date on evacuation decisions. If there are no predetermined evacuation zones in your area this does not mean that you will never receive evacuation instructions from local officials.


If you must evacuate your home:

  • Bring your emergency supply kit and only what you really need, such as your cell phone, charger, ID (eg, passport or driver's license), your medications, and cash.

  • Unplug appliances. If you have time, turn off the gas, electricity, and water.

  • Follow the routes that emergency workers recommend, even if there is traffic. The other routes could be blocked or flooded. Never drive through a flooded area – rushing water as low as 6 inches deep has the ability to stop or sweep away cars and other vehicles.

  • Contact your local emergency management office and ask if they have places of shelter for people with pets. Learn more about how to evacuate your home with your pet .

Hurricane watches or warnings


Knowing the difference between hurricane watches and warnings will help you and your family stay safe during a storm. Alerts mean severe conditions are not yet, but may occur in the near future. If there is a storm warning, it means dangerous weather is coming.


Hurricane Watch – A hurricane watch is an announcement that hurricane force winds are possible within the specified area in association with a tropical cyclone. A hurricane watch is issued 48 hours before the expected start.

Hurricane WarningHurricane Warnings are issued 36 hours in advance and are announced when gale-force winds are expected somewhere within the specified area in association with a cyclone. This warning can remain in effect for other hazards, such as flooding, even if the winds drop below hurricane force.

How to understand the path of a hurricane


Hurricanes, known generically as tropical cyclones, are low-pressure systems with organized storm activity that form over tropical or subtropical waters. They get their energy from the warm waters of the ocean.


In the image on the left, there are no clear storm bands. On the right, the disturbance has become a tropical storm and has "organized" with bands wrapped around the center. (NOAA Satellites / NOAA Education)



As storm systems develop into hurricanes, surface winds continually move in a circular motion. Meteorologists refer to this pattern as a "closed circulation." The direction of the circulation is different depending on where the storm is: it is counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.


This satellite image of Hurricane Michael from October 10, 2018 has arrows superimposed on top to show the closed circulation wind pattern that is characteristic of a hurricane. (NOAA Satellites / NOAA Office of Education)

These rotating winds lead to the development of the characteristic "eye" of the hurricane, the calm and clear center of the storm. The eye is surrounded by the eyewall, where the winds are strongest.

Anatomy of a Hurricane

1- Eye of the hurricane : The eye is a roughly circular area of ​​fair weather that is in the center of a severe tropical storm. The eye is the region of lowest pressure at the surface and the warmest temperatures at the top. Eye sizes range from 5 to 120 miles across, but most are 20 to 40 miles in diameter.


2- Hurricane eyewall : The eyewall is a ring of deep convection that borders the eye of the storm. This area has the highest surface winds of the tropical cyclone.


3- Spiral bands: Spiral bands are long, narrow bands of rain and thunderstorms that are oriented in the same direction as the movement of the wind. They are caused by convection (the vertical movement of air masses) and spiral toward the center of the tropical cyclone.



How to understand the hurricane cone we see in weather reports?


It is important to remember that the hurricane cone that we often see on television weather reports is NOT the impact cone.


The hurricane cone shows the likely path only of the STORM CENTER, but impacts from tropical systems may be felt far from the storm center. Therefore, the dangers of a hurricane generally extend outside the perimeter of the cone.


Hurricane Cone Example (NOT A CURRENT FORECAST)

How NOT to use the hurricane cone?

  • DO NOT use it to assess your risk of hurricanes or floods

  • DO NOT use it to determine if you should evacuate your area

What CAN you use the hurricane cone for?

  • To get a rough idea of ​​where the center of the hurricane might be

  • To find out how big the storm is currently

  • To find out where there are currently hurricane warnings

For more information on how to interpret the hurricane cone, watch the following video from the National Oceanic and Atmospheric Administration and select Spanish subtitles: https://www.nhc.noaa.gov/cone_usage.php

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