Thunderstorms occur when large air masses rise quickly into the atmosphere, forming huge cumulonimbus clouds. Severe air currents inside the clouds cause water droplets and ice crystals to crash into one another continually, and the friction between these particles creates static electricity in the cloud. Over time, opposite charges build between the top and bottom of the cloud, and the bottom of the cloud and the earth. When these opposing charges become intense, a gigantic spark occurs (lightning) which jumps the gap between the cloud and the earth. The thunder accompanying lightning is the noise produced by the discharge.
Hurricanes are high speed windstorms accompanied by torrential rains. They begin over the ocean where air rising from warm seas creates a severe low pressure zone. This zone draws air to it with such force the winds rotate around the core (the eye) at up to 185 mph. The 'eye' averages about 20 miles in diameter while the hurricane may be up to a few hundred miles in diameter. After the onset of a hurricane at sea, the storm moves slowly toward one of the poles and loses force as it moves into cooler areas or over land. Hurricanes are usually predicted by meteorologists well in advance of their occurrence.
One of the most destructive natural phenomena, tornadoes are swirling winds that spin at phenomenal speeds of up to 400 mph. Like hurricanes, they are caused by severe low pressure zones that attract winds with force. They have relatively small bases, a fact which greatly magnifies their destructive power. Tornadoes are difficult to predict and often strike without warning. Meteorologists expect to be able to predict a tornado in the near future.
Waterspouts are tornadoes over water which draw up large columns of water. If a waterspout moves from sea to shore, expect fish and other sea creatures to rain down!
Dust Devil -
Dust Devils' are small tornadoes over land that draw up dust and light debris. They are most common in desert areas.
Sundogs are mock suns that appear to the left or right of the sun when it is low on the horizon. They are caused by light refracted through ice crystals present in cirrus or cirrostratus clouds.
Rainbows are caused when sunlight penetrates raindrops and is broken into bands of red, orange, yellow, green, blue, indigo and violet. You can simulate a rainbow easily by placing your back to the sun and looking through the mist of a lawn sprinkler.
Aurora Borealis -
Aurora Borealis is caused when atomic particles from space react with atoms high in the atmosphere. Visible from Canada and the northern United States, auroras illuminate the night sky with pulsing curtains of coloured light.
Do any of these sound familiar to you? Here are their meanings...
"Red sky at night, sailor's delight. Red sky in morning, sailor take warning." (Red sunsets are usually followed by dry nights. A red morning sky means rain is on the way.)
"A sun-shiny shower, won't last half an hour." (Showers that happen while the sun shines are brief.)
"Mackerel sky and mare's tails make tall ships carry low sails." (Certain clouds are often followed by high winds.)
"Coming storms cause shooting corns." (Aches and pains are aggravated when a storm approaches.)