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Severe Weather

Thunderstorms and Lightning

The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Nearly 1,800 thunderstorms are occurring at any moment around the world. That’s 16 million a year! 

Despite their small size, all thunderstorms are dangerous. Every thunderstorm produces lightning, which kills more people each year than tornadoes. Heavy rain from thunderstorms can lead to flash flooding. Strong winds, hail, and tornadoes are also dangers associated with some thunderstorms.

Take the time NOW to understand these dangers and learn basic safety rules!


 

Lightning

  • Average 93 deaths and 300 injuries each year

  • Causes several hundred million dollars in damage to property and forests annually

Straight-line winds

  • Winds can exceed 100 mph!

  • One type straight-line wind, the downburst, can cause damage equivalent to a strong tornado

Large Hail

  • Causes nearly $1 billion in damage to property and crops annually

  • Costliest United States hailstorm: Denver Colorado, July 11 1990. Total damage was $625 million

Flash Floods/floods

  • The number ONE thunderstorm killer nearly 140 fatalities each year

  • Most flash flood deaths occur at night and when people become trapped in automobiles

Who’s Most at Risk from Thunderstorms?

From lightning:

  • People who are outdoors, especially under or near tall trees

  • People who are in or on water

  • People who are on or near hilltops

From Flooding:

  • People who are in automobiles when flash flooding occurs near them

From Tornadoes:

  • People who are in mobile homes and automobiles

What You Can DO!

Before the storm…

  • Know the county in which you live and the names of nearby major cities. Severe weather warnings are issued on a county basis

  • Check the weather forecast before leaving on extended periods outdoors

  • Watch for signs of approaching storms

  • Postpone outdoor activities if thunderstorms are imminent

When Thunderstorms Approach….

  • Remember: if you can hear thunder, you are close enough to the storm to be struck by lightning

  • Move to a sturdy building or car. Do not take shelter in small sheds, under isolated trees

  • Use phones only in an emergency

  • Do not take a bath or shower

  • Turn off electrical appliances

  • Get to higher ground if flash flooding or flooding is possible

If Caught Outdoors and No Shelter is nearby…

  • Find a low spot away from trees, fences, and poles

  • Make sure the place you pick is not prone to flooding

  • If you are in woods, take shelter under shorter trees

  • If you are boating or swimming, get to land and find shelter immediately!

If you feel your skin tingle or you hair stand on end, squat low to the ground on the balls of your feet. Place your hands on your knees with your head between them. Make yourself the smallest target possible, and minimize your contact with the ground.

What is a tornado?

A tornado is a violent rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes can produce massive destruction with wind speeds of 250 mph or more. Damage paths can be more than 1 mile wide and 50 miles long. The typical tornado moves from southwest to northeast, but they have been known to move in any direction. The average forward speed of a tornado is 30 mph but it may vary from stationary to 70 mph. Although tornadoes occur in many parts of the world, they are found most frequently in the United States Rocky Mountains during the spring and summer months. In an average year, 800 tornadoes are reported nationwide, resulting in 80 deaths and over 1,500 injuries.

How do we classify tornadoes?

Tornadoes are classified by wind speed and damage according to the Fujita Scale.

Where and when do tornadoes occur?

Tornadoes can occur anywhere at any time of the year. In the southern states peak tornado season is March through May when warm, moist gulf air mixes with the cooler air masses that extend into the south.

Who is most at risk from Tornadoes?

  • Everyone is at risk from a tornado.

    • The following groups of people are more at risk:

  • People in automobiles

  • The elderly, very young, and the physically or mentally impaired

  • People in mobile homes

How can I tell if a tornado is about to occur?

When conditions are favorable for severe weather to develop, a severe thunderstorm or tornado WATCH is issued by the National Weather Service. Weather Service personnel use information from weather radar, spotters, and other sources to issue severe thunderstorm and tornado WARNINGS for areas where severe weather is imminent. The warnings are passed on to local radio and television stations and are broadcast over local NOAA Weather Radio stations serving the warned areas. These warnings are also relayed to local emergency management and public safety officials who can activate local warning systems to alert communities.

In addition to keeping abreast of the latest watches and warnings issued,  there are certain environmental clues that Mother Nature provides us with:

  • Dark, often greenish sky,

  • Wall cloud,
  • Large hail,
  • Loud roar-similar to a freight train.

Where can I find out more information about tornadoes?

What is the difference between a Tornado Watch and a Tornado Warning?

A Tornado Watch means that tornadoes are possible in your area.

A Tornado Warning means that a tornado has been sighted or indicated by weather radar.

Protection against Tornadoes:

The National Weather Service alerts the public to sever weather hazards by issuing watches and warnings that are broadcast on the National Oceanic and Atmospheric Administration ( NOAA ) weather radio, television, and commercial radio. Meteorologists issue a tornado watch when weather conditions are favorable for the development of tornadoes and severe thunderstorms. Watches are often issued hours before severe weather develops and generally cover many counties or even several states. A tornado warning means that a tornado is occurring or is imminent. A warning is issued if a tornado has touched down, if a funnel cloud is present, or if Doppler radar indicates the presence of strong rotation in a thunderstorm updraft. The area covered by a warning is much smaller than a watch, usually only a county or two, or a portion of a county.

What to do if a tornado watch is issued:

  • When you here the Tornado Watch, keep your eyes on the sky for signs of a possible tornado and listen to the radio for the latest advice from the National Weather Service.

  • During a Tornado Warning, people should seek shelter immediately in a basement or in the interior portion of a building (a closet, interior hallway, or bathroom). Mobile homes and cars have a tendency to roll in high winds and should therefore be abandoned. Structures with large, free-span roofs, such as auditoriums, gymnasiums, and supermarkets, are subject to collapse and should also be avoided. If caught outside, a person should lie flat in a ditch and cover his or her head for protection from flying debris.