Hurricanes form in tropical regions where there are warm water (80 degrees Fahrenheit or better), moist air and converging winds. Three events must happen for hurricanes to form:
A continuing evaporation-condensation cycle of warm, humid ocean air
Patterns of wind with converging winds at the surface and strong,
simultaneous winds at higher altitudes
| A difference in air pressure (i.e., a pressure gradient) between
the surface and high altitude | |
Tropical depression: Swirling clouds and rain with wind speeds less than
38 mph (33 knots).
Tropical storm: Wind speeds of 39 to 73 mph (34 to 63 knots).
| Hurricane: Wind speeds greater than 74 mph (64 knots). | |
The proceeding is from http://www.howstuffworks.com/hurricane1.htm
Hurricane Warning: A warning that sustained winds 64 kt (74 mph or 119 kph) or higher associated with a hurricane are expected in a specified coastal area in 24 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continue, even though winds may be less than hurricane force.
Hurricane Watch: An announcement of specific coastal areas that a hurricane or an incipient hurricane condition poses a possible threat, generally within 36 hours.
Tropical Storm Warning: A warning for tropical storm conditions including sustained winds within the range of 34 to 63 kt (39 to 73 mph or 63 to 118 kph) that are expected in a specified coastal area within 24 hours or less.
Tropical Storm Watch: An announcement that a tropical storm poses or tropical storm conditions pose a threat to coastal areas generally within 36 hours. A tropical storm watch should normally not be issued if the system is forecast to attain hurricane strength.
The links below will help you learn what to do when a watch or warning is issued. Even more important, they will help you prepare before the hurricane season begins. Those who wait until a watch or warning are issued to obtain supplies have generally waited too long.
Tips to follow when
hurricane watches, warnings are issued.
A USA TODAY Online graphic explains some basic ways to prepare
your home for the hurricane season. Another file gives additional tips on
how to prepare for a
hurricane.
| More information on hurricane preparedness is available on the Federal
Emergency Management Agency's Hurricane
Page.
| An article from the
Federal Emergency Management Agency's hurricane page explains why tropical
storms should not be underestimated.
| Once a hurricane moves on and the winds die down, the danger isn't over. USA
TODAY Online text gives advice
on how to stay safe after a storm.
| The Metro/Dade
(Miami) Building Code Compliance Office has information on preparing for
hurricanes along with other useful tips for what to do after a storm hits.
| Improved warnings,
new shelters save thousands in Bangladesh | |
from http://www.usatoday.com/weather/huricane/whsafety.htm