1. THUNDERSTORMS!

2. Every thunderstorm needs:
Moisture: to form clouds and rain
Unstable air: warm air that can rise quickly
Lift: caused by cold fronts, breezes, or the sun’s heat

3. The Thunderstorm Life Cycle
Developing Stage
Towering cumulus cloud indicates rising air
Usually little if any rain during this stage
Lasts about 10 minutes
Occasional lightning

4. The Thunderstorm Life Cycle
Mature Stage
Most likely time for hail, heavy rain, frequent lightning, strong winds, and tornadoes
Storm occasionally has a black or dark green appearance
Lasts an average of 10 to 20 minutes but some storms may last much longer

5. The Thunderstorm Life Cycle
End Stage
Rainfall decreases
Can still produce a burst of strong winds
Lightning remains a danger
Downdrafts of cool air stop more warm air from rising into the cloud which causes thunderstorms to stop

6. What causes lightning?
Inside cloud, ice pellets and ice crystals are hitting each other
They exchange charges (+ and -)
Bottom of cloud becomes negatively charged
Ground underneath cloud becomes positively charged
Charges attract each other and reach toward each other
When they touch = shock!

7. Lightning Facts
The energy from one lightning flash could light a 100-watt light bulb for more than 3 months.
The channel of air through which lightning passes can be heated to 50,000°F—hotter than the surface of the sun!
The rapid heating and cooling of the air near the lightning channel causes a shock wave that results in the sound we know as “thunder.”

8. Lightning Safety
There is no safe place outdoors when a thunderstorm is nearby.
Lightning is attracted to the highest point in the area and to materials that easily conduct electricity, such as water, wiring, and metals.

9. How far away is the lightning?
Count the number of seconds between a flash of lightning and the sound of the resulting thunder.
Divide this number by 5 to get an estimate of the distance in miles to the lightning strike.