Thunderstorms

Thunderstorms

A thunderstorm develops in an unstable atmosphere when warm moist air near the earth’s surface rises quickly and cools. The moisture condenses to form rain droplets and dark thunder clouds.  At any given time, there are over 2000 thunderstorms in progress over the surface of the earth.

These storms are often accompanied by hail, lightning, heavy rain, high winds, and tornadoes. Thunderstorms are usually over in an hour, although a series of thunderstorms can last for several hours.

Lightning

During a thunderstorm the air is charged with electricity.  Bolts of lightning hit the ground at about 40 000 km/second – so fast that the series of strikes hitting the ground appear as a single bolt.  Lightning strikes the earth over 100 times each second and can be dangerous.  Keep the following precautions in mind to avoid injury.

 Stay inside.  DO NOT go out unless absolutely necessary.

 Stay away from open doors, windows, fireplaces, radiators, sinks, bathtubs, appliances, telephones, plumbing fixtures, metal objects and any other things which conduct electricity.

 Disconnect radios, computers, televisions and any sensitive electronic devices.  You can use a cell phone.

 DO NOT go to rescue the laundry on the clothesline as it conducts electricity.

If you are outdoors:

 Estimate how far away the lightning is.  Every second between the flash of lightning and the thunderclap equals 300 metres.  If you count fewer than 30 seconds, take shelter immediately in a building, ditch or hollow but never under a tree.

 If shelter is unavailable, crouch in the leap frog position.  Kneel on the ground and lean forward with your head lower than your back (but not touching the ground) and place your hands on your thighs.

 Avoid hilltops, open spaces, and metal objects such as fences, machinery, sheds, etc.

 DO NOT use or handle metal items such as tools, umbrellas, golf clubs, etc.

 DO NOT ride bicycles, motorcycles or golf carts.

 DO NOT go swimming or boating.  If swimming or in a boat, get back to shore immediately.

 You may resume activity 30 minutes after the last clap of thunder.

If you are in a vehicle:         

 Stay in your vehicle.

 DO NOT touch metal surfaces inside the vehicle.

 DO NOT park near trees or other high objects.

First Aid

If you see someone struck by lightning, call 911 immediately.  Administer first aid such as mouth-to-mouth resuscitation.  Lightning victims are not “charged” and, therefore, not dangerous to touch.