Denver's Lightning Severe Weather Page

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
600 AM MDT FRI APR 24 2009

...WHEN THUNDER ROARS...GO INDOORS...

Thunderstorms produce some of the most dangerous weather on earth... including tornadoes...flash floods...large hail…and destructive straight-line winds. However…the most dangerous aspect of thunderstorms in Colorado is usually lightning.

For the last 10 years…lightning has killed and injured more people in Colorado than any other thunderstorm hazard...with an average of 3 fatalities and 15 injuries each year. These numbers are probably higher as studies indicate that many lightning casualties... especially injuries...are not reported. In 2008…there were 4 documented fatalities and 10 additional people injured by lightning in Colorado.

In addition to producing casualties to people...lightning also ignites most of the forest and rangeland fires in the Centennial State...with an average of about 2500 wildfires each year. Many of these wildfires occur when lightning is generated from thunderstorms which produce little or no rainfall. This type of lightning is commonly referred to as dry lightning.

Nearly half a million lightning flashes strike the ground in Colorado every year. Each stroke contains millions of volts of electricity...enough to supply power to several homes for a month. Lightning also heats the surrounding air up to 50 thousand degrees Fahrenheit...creating a shock wave that results in thunder

Lightning is unpredictable and occasionally behaves in a strange manner.It can destroy one object without touching another one nearby. Although lightning typically strikes the tallest object in an area…that is not always the case.

The safest thing for you to do if you are outside and lightning or thunderbegins to occur is to immediately get inside a substantial building...such as a house...a store or a church. A hard topped vehicle such as a car...a SUV or a bus also offer excellent protection from lightning. Once inside a substantial building or hard topped vehicle...keep all windows and doors closed…and do not touch any metal inside the vehicle. It is then recommended that you wait at least 30 minutes from the last rumble of thunder before returning outside.

A recent lightning safety study has shown that 95 percent of the people who were struck by lightning while outdoors had a nearby substantial building or vehicle nearby. Remember...there is NO safe place outdoors when lightning is occurring. Do NOT seek shelter under picnic shelters...dugouts...porches...trees…carports or tents. These types of structures are NOT safe when lightning is occurring.

Once inside a substantial building...stay off corded telephones since the electrical discharge can travel along the telephone lines and produce fatal results. Stay away from water...such as showers... tubs and sinks. Indoor swimming pools are not safe when lightning is occurring. It is also recommended that you unplug sensitive electronics such as computers when lightning is expected to occur nearby.

The best defense to protect yourself against a lightning strike is to plan ahead and avoid being caught where you might be vulnerable. Check the weather forecasts prior to venturing out...especially if you are heading into the mountains. Plan your outdoor activities for early in the day before thunderstorms typically develop. Stay tuned to NOAA Weather Radio All Hazards and check the National Weather Service forecasts at www.weather.gov.

It is very important that all sports leagues and other outdoor groups have a lightning response plan that is understood and consistently applied for the safety of the participants. Part of the plan would include a designated weather watcher at each outdoor event with the authority to postpone or cancel the event due to the threat of lightning.

Remember...if thunderstorms threaten…seek shelter in a substantial building or in an enclosed metal roof vehicle. For more information on lightning safety...please check out the web site www.lightningsafety.noaa.gov. For more information about lightning in Colorado...please go to the Colorado Lightning Resource Webpage at:

www.weather.gov/pub/ltg.php

National Weather Service Weather Forecast Office