Thunderstorms

LIGHTNING

Lightning is an underrated hazard that occurs during thunderstorms, tornadoes, hurricanes and volcanic eruptions. When thunderstorms threaten your area get inside a home, large building or car (not convertible).

SAFETY TIPS

1. Inside a home, avoid bathtubs, water faucets and sinks because metal pipes can conduct electricity. Avoid using the telephone, except for emergencies.

2. If outside, with no time to reach a safe building or an automobile, follow these rules:

• In a forest, seek shelter in a low area under a thick growth of small trees.

• In open areas, go to a low place such as a ravine or valley. Be alert for flash floods.

• Do not stand underneath a natural lightning rod, such as a tall, isolated tree in an open area.

• Do not stand on a hilltop, in an open field, on the beach or in a boat on the water.

• Avoid isolated sheds or other small structures in open areas.

• Get away from open water

• Get away from anything metal tractors, farm equipment, motorcycles, golf clubs, and bicycles

• Stay away from wire fences, clotheslines, metal pipes, rails and other metallic paths which could carry lightning to you from some distance away.

3. If you are isolated in a level field or prairies and you feel your hair stand on end (which indicates that lightning is about to strike), drop to your knees and bend forward putting your hands on your knees. Do not lie flat on the ground.

4. Learn CPR it could very well save someone's life who may or may not have been struck by lightning.

LIGHTNING FYI

• The average Lightning Stroke is 6 miles long

• The temperature of lightning's return stroke can reach 50, 000 degrees Fahrenheit.

• The average Thunderstorm is 6-10 miles wide

• The average thunderstorm travels at a rate of 25 miles per hour.

• Once the leading edge of a thunderstorm approaches to within 10 miles, you are at immediate risk due to the possibility of lightning strokes coming from overhanging

• anvil clouds. Because of this, many lightning deaths and injuries occur with clear skies directly overhead.

• On average, thunder can only be heard over a distance of 3-4 miles, depending on humidity, terrain, and other factors.

• Approximately 100, 000 thunderstorms occur in the United States each year.

• Approximately 10% of all thunderstorms are severe enough to produce high winds, flash floods and tornadoes

• Thunderstorms cause an average of 200 deaths and 700 injuries in the United States each year

• Between Jan. 1940 - 1974 a total of 7, 000 Americans lost their lives due to lightning strikes.

ANOTHER WEATHER WORRY

Microbursts

According to the NOAA Comprehensive Glossary of Weather Terms for Storm Chasers, a microburst can occur with precipitation or without and may or may not produce lightning. Microbursts are synonymous with downbursts or downdrafts, that is a small concentrated downdraft that may affect an area less than 2.5 miles across. Most microbursts are rather short lived ( 5 minutes or so). The strong winds produce damage comparable to a tornado, but no loss of life has been attributed to microbursts.

Observing ground conditions is your best bet to identifying the location of microbursts. During dry conditions microbursts will produce visible signs of dust plumes, or rings of blowing dust. During wet microbursts, the direction and shape of precipitation shafts also known as virga can be tell-tale signs. In wet microbursts, the shaft is bent at the bottom in a horizontal direction making it look as though the thunderhead has a rain boot.


For More Information please contact:

Mike Stever

Program Manager

Salt Lake City Emergency Preparedness

(801) 535-6030