Tornado is the most damaging storm.The word tornado come from Spanish “Tronada” that mean thunder storm. Also come from Latin language ”Tonare” which mean rumbling. According to the story,the word tornado was taken from combination between ronada and Tornar in Spanish. Tornado is air column which rotate very fast and form relation between cumulonimbus cloud. Usually tornado has wind velocity between 177 km/hours or more with reach average 75 meters and attack several kilometers before disappearing. Several tornado which reach wind velocity more than 300-480 km/hours have wide more than one mile and can survive in the surface more than 100 km.

    Tornado generally happens in the afternoon to evening. In America, tornado happens between 15.00-21.00. Although tornado has been research by the scientist, in every continent, most of tornado happens in America. In America, most of tornado happen in tornado alley in middle-west America. Other area which generally happen tornado are South Canada, South Africa, East and south Asia, Middle Europe, Italy, West Australia, New South Wales, and Indonesia. In Indonesia, usually happen in Sumatra and Java.

    Tornado has some types. They are weak, strong and violence tornado. Weak tornado include 88% of all tornado. The wind velocity is less than 112 mph. Weak tornado happen about 1-10 minutes. Death because of this tornado are about 5% of the total death because of tornado. Strong tornado include 11% of all tornado. The wind velocity is between113-206 mph.This tornado happens in 20 minutes or more. The death because of strong tornado is about 30% of the total death because of tornado. Violent tornado is rarely happen. This include 1% of all tornado. The wind velocity is more than 205 mph or more. This tornado happens in one hours or more. Although rarely happen, this tornado can cause death about 70% of the total death because of tornado.

    Before tornado happens, it has several signal. First, the sky seems dark. Then happen ice rain around the area, usually 20-25 minutes. After that, the situation will calm, but the sky become darker. Fourth, cloud moving around the area. Fifth, the sound of tornado heard. At the beginning, the sound like water fall, but in the process of time it will change until like jet plane which is very loud. A tornado usually move from southwest to north east.

    The change of air layer is the cause of tornado. In this case, if the cold air layer is above the hot air layer, the hot air layer go up with velocity about 300 km/hour. The air which infiltrating from this side, cause wind rotate and form Tornado.

Which area in tornado often occurs ?