Hurricane Season Fast Facts

Here’s a look at what you need to know about the Atlantic hurricane season, which runs from June 1 to November 30.

The National Weather Service defines a hurricane as “an intense tropical weather system with well-defined circulation and sustained winds of 74 mph (64 knots) or higher.”

The peak of the season is from mid-August to late October.

In the western Northern Pacific, hurricanes are called typhoons.

Similar storms in the Indian Ocean are called cyclones.

Hurricanes are rated according to intensity on the Saffir-Simpson Hurricane Wind Scale.

The 1-5 scale estimates potential property damage.

A Category 3 or higher is considered a major hurricane.

A hurricane watch indicates the possibility that a region could experience hurricane conditions within 48 hours.

A hurricane warning indicates that tropical-storm-force winds of at least 74 mph are expected within 36 hours.

Hurricane Development:
There are three stages of development: tropical depression to tropical storm to hurricane.

Tropical depression – when a cluster of thunderstorms organizes under the right atmospheric conditions for a long enough time, with maximum sustained winds of 38 mph (33 knots) or lower.

Tropical storm – a tropical depression that has intensified to the point where its maximum sustained winds are between 39-73 mph (34-63 knots). During this time, the storm itself becomes more organized and begins to become more circular in shape — resembling a hurricane. This is when the storm is named.

Hurricane – develops from a tropical storm as surface pressures continue to drop, and sustained wind speeds reach 74 mph (64 knots) or higher, with a pronounced rotation developing around the central core.

Hurricane Categories:
From National Hurricane Center/NOAA (National Oceanic and Atmospheric Administration)

The Saffir-Simpson Hurricane Wind Scale is a 1-5 rating based on the hurricane’s present intensity.

It estimates potential property damage.

Sustained wind speed is the determining factor in the scale.

Category One Hurricane
Winds 74-95 mph (64-82 kt or 119-153 km/hr).

No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery and trees.

Some damage to poorly constructed signs and coastal road flooding with minor pier damage.

Damage to power lines and poles could result in power outages lasting several days.

Category Two Hurricane
Winds 96-110 mph (83-95 kt or 154-177 km/hr).

Some roofing material, door, and window damage of buildings. Considerable damage to shrubbery and trees with some trees blown down. Considerable damage to mobile homes, poorly constructed signs and piers.

Small craft in unprotected anchorages break moorings.

Power outages could last from several days to weeks.

Category Three Hurricane
Winds 111-129 mph (96-112 kt or 178-208 km/hr).

Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Many large trees will be uprooted and blown down, blocking roads. Mobile homes and poorly constructed signs are destroyed.

Evacuation of low-lying residences within several blocks of the shoreline may be required.

Electricity and water will be unavailable for several days to weeks.

Category Four Hurricane
Winds 130-156 mph (113-136 kt or 209-251 km/hr).

More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows.

Power outages will last from weeks to possibly months, with most of the area also being uninhabitable for weeks or months.

Category Five Hurricane
Winds greater than 157 mph (137 kt or 252 km/hr).

Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. All shrubs, trees and signs blown down. Complete destruction of mobile homes. Severe and extensive window and door damage.

Massive evacuation of residential areas on low ground within 5-10 miles (8-16 km) of the shoreline may be required.

Power outages will last from weeks to possibly months, with most of the area also being uninhabitable for weeks or months.

Once a storm system with counter-clockwise circulation and sustained wind speeds of 39 mph or greater is identified by the National Hurricane Center in Miami, a name from the list is assigned to the storm.

There are nine regional lists of names: Atlantic, Eastern North Pacific, Central North Pacific, Western North Pacific Ocean/South China Sea, Australian Region, Port Moresby/Papua New Guinea, Fiji Region, Southwest Indian Ocean and North Indian Ocean.

Using women’s names became the practice during World War II, following the use of a woman’s name for a storm in the 1941 novel “Storm” by George R. Stewart.

In 1979, the list of hurricane names for the Atlantic regions began to include male names.

Six separate name lists are developed and agreed upon by the World Meteorological Organization.

The lists are rotated every six years.

Names associated with storms that have caused significant death and/or damage are retired from the list. Camille (1969), Andrew (1992), Opal (1995), Floyd (1999), Ivan (2004), Katrina (2005), Ike (2008) and Sandy (2012) have all been retired from the list. Once a name is removed, another name replaces it.

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