Some of the most destructive hurricanes have been category five hurricanes. The names of hurricanes that are particularly destructive are struck off the name lists and replaced by other names with the same initial. There are six separate hurricane name lists, and a hurricane cannot get the same name more often than once every six years. Hurricane naming lists are alphabetical, and the names alternate between male and female names. Hurricanes are named by the World Meteorological Organization ( WMO). Hurricanes are named so they can be easily referred to in media and by warning services. Charley hit Florida as a category 4 hurricane. Most of the area will be uninhabitable for weeks or months.ĭestruction by the hurricane Charley in the United States in 2004. Power outages will last for weeks to possibly months. Fallen trees and power poles will isolate residential areas. Most of the area will be uninhabitable for weeks or months.Ī high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Power outages will last weeks to possibly months. Most trees will be snapped or uprooted and power poles downed. Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Electricity and water will be unavailable for several days to weeks after the storm passes. Many trees will be snapped or uprooted, blocking numerous roads. Well-built framed homes may incur major damage or removal of roof decking and gable ends. Near-total power loss is expected with outages that could last from several days to weeks. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Well-constructed frame homes could sustain major roof and siding damage. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days. Large branches of trees will snap and shallowly rooted trees may be toppled. Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. If a storm's maximum sustained surface winds (one-minute average) are at least 74 mph, it is called a hurricane.Ī hurricane's strength and destructive potential is described on the Saffir-Simpson hurricane wind scale as follows: Saffir-Simpson Hurricane Wind Scale Category If conditions are favourable, tropical storms can become hurricanes. Tropical depressions become tropical storms, when their maximum sustained surface winds (one-minute average) exceed 38 mph, but are no more than 73 mph. During La Niña years the opposite happens. To strengthen, tropical cyclones require the presence of Coriolis force, which doesn't exist close to the equator.ĭuring El Niño years the likelihood of hurricanes grows in the Eastern Pacific, but lowers in the Northern Atlantic. A location of no closer than around 300 miles from the equator.Small wind speed and direction fluctuations between different height levels.This helps the storm to form and strengthen. With strong condensation a lot of heat is released into the surrounding air. The condensation of water vapour needs to be strong around the center of the tropical depression.Water vapour evaporation from the sea surface. This is aided by strong winds towards the low pressure center.

Sea surface temperatures of 79–80 ☏ in a thick enough layer.In the North Atlantic or Eastern Pacific these cyclones are called hurricanes.Ĭonditions that favour hurricane formation are:

In favourable conditions a tropical depression can strengthen into a tropical cyclone. Photo: Foreca Tropical depressions can strengthen and become hurricanesĪs the low pressure center forms, its wind speeds are below 40 mph. When a cluster of thunderclouds begin to circle around a low pressure center, a tropical depression may form. This can mark the onset of hurricane formation.

In favourable conditions a low pressure center appears in conjunction of these thunderstorm clusters, and the thunderstorms begin to circle it counterclockwise. The storms move towards the Western North Atlantic carried by easterly air currents. These seeds are often clusters of thunderstorms close to the African West coast. Most of the hurricanes that form in the North Atlantic, Gulf of Mexico or East of Central America are triggered by so called 'African seeds'. An 'African seed' can trigger hurricane formation In Northwestern Pacific hurricane-like storms are called typhoons, and in the Indian Ocean and South Pacific areas they are called tropical cyclones. Hurricanes are tropical cyclones found either in the North Atlantic or Eastern Pacific areas.Ī tropical cyclone's name depends on its geographic location.

Hurricane track map