Hurricane Preparedness 2011 - Basics & History

Hurricane Basics & History

First In the 2011 Series

Hurricane Preparedness Week playlist on YouTube

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President Obama declared May 22-28 “National Hurricane Preparedness Week." FEMA, along with the National Oceanic and Atmospheric Administration (NOAA), is helping to raise awareness of steps that can be taken to help protect citizens, and their communities and property. 

What is a Hurricane?

A hurricane is a type of tropical cyclone, which is a generic term for a low pressure system that generally forms in the tropics. The cyclone is accompanied by thunderstorms and, in the Northern Hemisphere, a counterclockwise circulation of winds near the earth's surface. Tropical cyclones are classified as follows:

* Sustained winds A 1-minute average wind measured at about 33 ft (10 meters) above the surface. ** 1 knot = 1 nautical mile per hour or 1.15 statute miles per hour. Abbreviated as "kt".

Tropical Depression
An organized system of clouds and thunderstorms with a defined surface circulation and maximum sustained winds* of 38 mph (33 kt**) or less

Tropical Storm
An organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds of 39-73 mph (34-63 kt)

Hurricane
An intense tropical weather system of strong thunderstorms with a well-defined surface circulation and maximum sustained winds of 74 mph (64 kt) or higher

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

• A hurricane watch means a hurricane is possible in your area. Be prepared to evacuate. Monitor local radio and television news outlets or listen to NOAA Weather Radio for the latest developments.
• A hurricane warning is when a hurricane is expected in your area. If local authorities advise you to evacuate, leave immediately.

Hurricanes are classified into five categories based on their wind speed, central pressure, and damage potential. Category Three and higher hurricanes are considered major hurricanes, though Categories One and Two are still extremely dangerous and warrant your full attention.The following chart details the categories and the damage that can result from a storm with that strength.

 
Saffir-Simpson Hurricane Scale

Scale Number (Category)	Sustained Winds (MPH)	Damage	Storm Surge
1	74-95	Minimal: Unanchored mobile homes, vegetation and signs.	4-5 feet
2	96-110	Moderate: All mobile homes, roofs, small crafts, flooding.	6-8 feet
3	111-130	Extensive: Small buildings, low-lying roads cut off.	9-12 feet
4	131-155	Extreme: Roofs destroyed, trees down, roads cut off, mobile homes destroyed. Beach homes flooded.	13-18 feet
5	More than 155	Catastrophic: Most buildings destroyed. Vegetation destroyed. Major roads cut off. Homes flooded.	Greater than 18 feet

Hurricane History

2010 Atlantic Hurricane Season Track Map (click to enlarge)


In the following article, we look at the 2010 Hurricane season in review, comparing the forecast to actual results.   We also look at NOAA and Colorado State University forecasts for the 2011 Season.

NOAA 2011 Hurricane Season Predictions

Hurricane Assessments	Billion Dollar Storms
9/03: Hurricane Isabel 12/02: Super Typhoon Pongsona 6/01: Tropical Storm Allison 9/96: Hurricane Fran 7/96: Hurricane Bertha 9/95: Hurricane Marilyn 7/94: Tropical Storm Alberto 9/92: Hurricane Iniki 8/92: Hurricane Andrew 9/89: Hurricane Hugo NHC Archive of Hurricane Seasons	10/05 Hurricane Wilma 9/05: Hurricane Rita 8/05: Hurricane Katrina 9/03: Hurricane Isabel 9/99: Hurricane Floyd 9/98: Hurricane Georges 8/98: Hurricane Bonnie 9/96: Hurricane Fran 10/95: Hurricane Opal 7/94: Tropical Storm Alberto 8/92: Hurricane Andrew Other events since 1980

Central North Pacific Hurricane History (1800s - present)

(Compiled by the Central Pacific Hurricane Center, Honolulu).

We will continue coverage of Hurricane Preparedness Week by looking at some of the hazards starting tomorrow.  Additional Hurricane information can be found in our static Weather tab.