Formation: Storms form in disturbed area of the ocean.

Tropical Depression: Thunderstorms swirl around a centre.

Tropical Storm: An organised system of clouds and thunderstorms with a defined circulation and top winds of 63 kph (39 mph) to 118 kph (74 mph).

Hurricane Watch: Hurricane conditions possible within 36 hours.

Hurricane Warning: Hurricane conditions expected within 24 hours.

Hurricane: An intense tropical weather system with a well-defined circulation and wind speeds of 118 kph (74 mph) or higher.

Hurricanes are categorized according to their wind speed:

  • Tropical storm: winds 39-73 mph
  • Category One: winds 74-95 mph
  • Category Two: winds 96-110 mph
  • Category Three: winds 111-130 mph
  • Category Four: winds 131-155 mph
  • Category Five:winds 156 mph and up