5 Key Facts About Hurricanes and Tornadoes

Hurricanes and tornadoes form in warm, damp air when winds blow into each other from opposite directions. Wind speeds from tornadoes far exceed hurricanes, though hurricanes typically cause more damage.

Here are five key facts about hurricanes and tornadoes from the National Weather Service.

Hurricanes

  • SPEED: A hurricane is a tropical storm with sustained winds of 74 miles per hour or more.
  • SIZE: Hurricane winds blow in a large spiral around a relative calm center known as the “eye.” The eye is generally 20 to 30 miles wide and the storm may extend outward 400 miles.
  • DURATION: Hurricanes last for several hours and can last for more than 2 weeks over open waters.
  • DAMAGE: A hurricane damages structures through storm surge, rainfall-caused flooding, as well as high wind impacts.
  • SEASON: The Atlantic Ocean hurricane season officially begins on June 1 of each year and continues until November 30.

Tornadoes

  • SPEED: A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud and winds swirling at 40-320 mph. It is usually spawned by a thunderstorm (or as a result of a hurricane).
  • SIZE: Winds spiral around an “eye” of descending air, surrounded by a strong upward current. The average diameter of a tornado tends to be a mile or smaller.
  • DURATION: Most tornadoes last less than 10 minutes. However, some have been known to last over an hour.
  • DAMAGE: Damage is caused primarily from extreme winds and wind-blown debris.
  • SEASON: Tornado season is generally March through August. Also, over 80 percent of all tornadoes strike between noon and midnight.

Fujita Scale Level

Keep in mind most tornadoes last less than 10 minutes while hurricanes are sustained and can last for hours.

  • Category O/F0 Wind Speed — Hurricane is N/A, a Tornado is 40-72 mph
  • Category One/F1 Wind Speed — Hurricane is 74-95 mph, a Tornado is 73-112 mph
  • Category Two/F2 Wind Speed — Hurricane is 96-110 mph, a Tornado is 113-157 mph
  • Category Three/F3 Wind Speed — Hurricane is 111-130 mph, a Tornado is 158-206 mph
  • Category Four/F4 Wind Speed — Hurricane is 131-155 mph, a Tornado is 207-260 mph
  • Category Five/F5 Wind Speed — Hurricane is 155 mph +, a Tornado is 261-320 mph

The National Oceanic & Atmosphere Administration premiered the Enhanced F Scale for Tornado Damage in early 2006, and it went into effect in 2007. The original scale classified tornadoes based on damage to homes, the new one classifies tornadoes by the degree of damage to different structures – mobile homes, offices, malls, etc. – as well as homes.