Hurricane categories: the Saffir-Simpson Scale

There's not much hurricane news lately (which is a good thing), so let's take a look at some definitions.

Storms are classified into categories, ranked by their maximum sustained winds. (Sustained just means constant, rather than a temporary gust.) The ranking system is called the Saffir-Simpson Scale.

Tropical depressions are storms with winds less than 39 mph.

A tropical storm has winds of 40 to 74 mph. At this point the storm is given a human name. (See previous post for a list of this year's names.)

Hurricanes are divided into five numbered categories. The higher the number, the more severe the storm.

A Category 1 hurricane has winds of 74 to 95 mph. It typically creates a 4 to 5 foot storm surge and causes minimal damage

Category 2 hurricanes have winds of 96 mph to 110 mph with a storm surge of 6 to 8 feet.

Category 3 hurricanes have winds of 111 mph to 130 mph and creates storm surges of 9 to 12 feet.

A Category 4 hurricane has winds of 131 mph to 155 mph, causing storm surges 13 feet to 18 feet high.

A rare Category 5 hurricane has winds above 155 mph and can cause a storm surge higher than 18 feet.

Franklin forms in Bahamas

There's a new tropical storm in the Atlantic. Franklin is near the Bahamas, with winds of 45 mph. It's projected to turn north, then northeast, which would take it away from land.

See the projected path map.

2005 Hurricane Names

Here is the official list of hurricane and tropical storm names for this year.

Arlene
Bret
Cindy
Dennis
Emily
Franklin
Gert
Harvey
Irene
Jose
Katrina
Lee
Maria
Nate
Ophelia
Philippe
Rita
Stan
Tammy
Vince
Wilma

Hurricane Emily hits northeastern Mexico

Hurricane Emily crashed into northeastern Mexico as a strong Category 3 storm Wednesday, its 125 mph winds battering buildings and beaches and forcing thousands along the Gulf of Mexico to seek safer ground.

The eye of the storm came ashore just before dawn near San Fernando, a town about 80 miles south of the U.S.-Mexico border. The National Hurricane Center in Miami said hurricane force winds extended outward 70 miles. Tropical storm-force winds blew over south Texas.

Read the full story.

Hurricane Emily gain strength in Gulf

Hurricane Emily gathered strength in the Gulf of Mexico for a second strike against Mexico and south Texas late Tuesday, after ripping roofs off resort hotels and stranding thousands of tourists in the Yucatan Peninsula.

Emily hit the Mayan Riviera on Monday as a fierce Category 4 storm with 135 mph winds, causing millions of dollars in damage. Hundreds of local residents were left homeless, but no deaths or major injuries were reported.

NASA released this photo a few minutes ago:



Read the full story.

Hurricane Emily death toll up to 8

Hurricane Emily lashed beach resorts on Mexico's Yucatan Peninsula, where thousands of tourists were evacuated or took refuge in shelters while the storm toll across the Caribbean rose to eight dead.

The 215 kilometer (135 mile) an hour winds tore down trees and power lines but no casualties were immediately reported in the coastal resorts around Cancun -- renowned for its Palm tree lined beaches.

Emily is blamed for 8 deaths in the Caribbean, five of them in Jamaica.

Read the full story.

Emily slams into Yucatan

Hurricane Emily slammed into Mexico's Yucatan Peninsula on Monday as a powerful Category 4 storm, snapping concrete utility poles with its winds of 135 mph and punishing waves along the region's famous white-sand beaches.

Emily made landfall near Tulum — 100 miles south of Cancun.

Read the full story.

Hurricane Emily heads for Yucatan

Mexican officials launched the evacuation of 85,000 people across more than 100 miles of coastline and ordered the relocation of 30,000 tourists in Cancun. The state oil company began evacuating more than 15,000 workers from its offshore platforms in the Gulf of Mexico.

The Category 4 storm was on track to pass close to Grand Cayman Island overnight before smashing into the Yucatan Peninsula on its way to the Gulf of Mexico and possibly southern Texas next week.

Read the full story.

Hurricane Emily strengthens as it passes Jamaica

Hurricane Emily strengthened as it began passing south of Jamaica with 145 mph winds on Saturday, while Mexico prepared to evacuate tourists from the Yucatan peninsula as it was next in line for a direct hit from the second major hurricane of the Atlantic season. The storm was expected to pass near Grand Cayman Island on Sunday.

Read the full story.

Emily now a category 4 hurricane

Hurricane Emily has strengthened to a Category 4. The storm blasted out windows, flooded two hospitals and tore roofs from homes as it blew over Grenada and gathered force in the eastern Caribbean with winds of 135 mph. At least one person was killed.

Emily is currently projected to move just south of Jamaica late Friday or Saturday, pass the Cayman Islands Saturday and hit Mexico's Yucatan Peninsula on Sunday night.

Grenada Braces for Tropical Storm Emily

Grenadian police ordered people off the streets and businesses closed Wednesday as Tropical Storm Emily threatened an island still recovering from the devastation of Hurricane Ivan last year.

Emily is not currently expected to hit the continental United States. Current forecasts have it headed for Mexico's Yucatan Peninsula.

Tropical Storm Emily heads westward

Here's the latest advisory:

A HURRICANE WATCH REMAINS IN EFFECT FOR BARBADOS...GRENADA...THE GRENADINES...ST. VINCENT...AND ST. LUCIA. A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA WITHIN 36 HOURS. A HURRICANE WARNING WILL LIKELY BE REQUIRED FOR ALL OR PART OF THE WATCH AREA LATER THIS AFTERNOON.

A TROPICAL STORM WATCH REMAINS IN EFFECT FOR THE ISLAND OF TOBAGO. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA WITHIN 36 HOURS.

INTERESTS ELSEWHERE IN THE EASTERN CARIBBEAN SHOULD MONITOR THE PROGRESS OF EMILY.

South begins recovery from Dennis

About a quarter of million people in the Florida panhandle are without power today, in the aftermath of Hurricane Dennis. It may take weeks to restore electricity to everyone.

Dennis has been downgraded to a tropical depression, as it moves into the lower Ohio and mid-Mississippi Valleys.

Dennis moves through Alabama

Hurricane Dennis moved through Alabama overnight, causing an estimated $1-2.5 billion in damage. The storm had less impact than Ivan, since Dennis moved faster, and had a smaller area of hurricane-force winds.

Dennis comes ashore

Hurricane Dennis made landfall in the Florida Panhandle about 20 minutes ago, between Navarre Beach and Pensacola Beach. This is within 50 miles of where Hurricane Ivan hit last fall. Dennis is a stronger storm.

Dennis brushes Keys, heads for Florida Panhandle

Hurricane Dennis moved into the Gulf of Mexico Saturday. The eye missed the Florida Keys, but widespread flooding and power outages were reported.

The storm has strengthened back to a strong Category 4. It will make landfall somewhere between the Florida Panhandle and Louisiana, an area still recovering from last fall's Hurricane Ivan.

Hurricane Dennis death toll now over 30

Dennis is blamed for at least 32 deaths in the Caribbean.

The storm has weakened to a Category 1, but is expected to strengthen again as it enters the Gulf of Mexico.

Hurricane Dennis slams Cuba, heads for Florida

Hurricane Dennis hit Cuba today with 150 mph winds, making it a dangerous Category 4 storm. An estimated 85% of powerlines are down on the island.

At least 5 people were killed Thursday in Haiti and Jamaica by the storm.

Most of the Florida Keys have been evacuated, with Dennis expected to enter the Gulf of Mexico and head toward the Florida Panhandle. At this hour, it looks like most of the west coast of Florida will be spared the brunt of the storm.