Dark thunderclouds form on got humid days. A storm cloud is usually about 3 miles across and 5 miles high. Often, an individual thunderstorm is just one "cell" in a group of storms. Sometimes a single cell can become a "superstorm" and can be more than 30 miles across. If a storm is overhead, you can hear thunder at the same time you see lightning. If it is not overhead, you can see the lightning first because light travels much faster than sound. If you count the seconds between the lightning and the thunder and divide by five, that gives you a rough idea of how far away the storm is in miles.

Thunderclouds form when warm wet air surges upward and cools dramatically high in the sky. Inside these clouds some of the water freezes and strong air currents make the ice and water droplets bump together. This creates a buildup of static electricity. Positive charge piles up at the top of the cloud; negative charge piles up at the bottom and tries to escape to the ground. When the difference between the charges is large enough, a lightning stroke flashes either from the bottom to the top of the cloud (sheet lightning) or from the bottom of the cloud to the ground. The lightning heats the air around it to an incredible 54,000 * F, 5 times hotter than the surface of the sun. This heat causes the air to expand very fast - faster than that of the speed of sound. It is this which causes the crash of thunder.

LIGHTNING KILLS. During a lightning storm you can be killed by: the direct impact of a lightning bolt from above, being electrocuted by being adjacent to an item that is struck. Be killed or injured by being on the current path.Cloud to cloud lightning can be dangerous to hang gliders or glider pilots. Cloud to ground lightning are fatal 30% of the time if struck by a bolt. Ground to cloud lightning is extremely hot as you are close to the source, the ground. If you are in its path (at the origin of strike) you are cooked!!

If you are in a situation where you could be struck by lightning, look for these warning signs, and act quickly. Your hair standing on end, or a tingling sensation over your entire body may mean you are about to have a bad day. A crackling sound in the air means static charge is building, and a strike is possible anywhere. Try hard not to be standing in an open field while lightning is occurring. Never, ever, stand under a tree. No matter how hard it is raining, a tree is a stupid idea. Lightning will seek to connect with the highest object in the area, sometimes two. The charge can also travel through the ground, or straight from the branches to you.

If your hair stands straight up, put your feet together, crouch down, and put your hands over your ears. QUICKLY! If you are wearing shoes with spikes in them or carry a metal backpack get them off if possible.

Ridges help produce the vertical updrafts and the rain cloud conditions which generate lightning. Projections serve to trigger lightning strokes.

A climber should avoid being on exposed peaks or ridges, or in an unprotected flat area during an electrical storm. You should not climb if a storm is predicted. Avoid being under prominent or isolated trees. If you are caught in an exposed place, and you have some time before the storm reaches you, you should get as far down the mountain and away from exposed ridges as you can. Especially avoid ridges that dominate the skyline. If lightning is striking nearby, at once seek a place will protect you from direct strikes and ground currents. A flat shelf, a slope, or a slightly raised place dominated by nearby high point would give protection from lightning. If there is any choice always select a dry spot.