Read the passage and answer the following questions. Give no more than five words in each answer. The Causes and Effects of Tornadoes A large thunderstorm can produce tornadoes, the large, fast-moving funnels of wind that cause damage and deaths annually in America. Tornadoes can appear in groups, but even one can leave devastating effects in a very short time. Some have destroyed entire small towns in minutes. Tornadoes form in conjunction with thunderstorms in places where there is moist, warm air ahead of easterly-heading cold fronts. They tend to form in the winter and early spring in the central and southern United States, and in the summer in northern states. In the mountainous areas where air close to the ground flows upward to higher terrain, the wind speed increases and changes its direction in a storm. This leads to an invisible, horizontal spinning effect that is tilted vertically by rising air, forming the tornado. A funnel cloud extending down from a wall cloud is the sure clue of a tornado, but there are other visual clues that one may be forming. The wall cloud itself is one. The skies will turn a dark, often greenish color around thunderstorm cells powerful enough to produce a tornado. The same storm will produce larger than normal hail and rain bursts. About 70 percent of all tornado formations are considered “weak,” with winds that reach 110 mph or or less. They last for one to 10 minutes and account for less than 5 percent of tornado deaths. Strong tornadoes have winds that reach between 110 and 205 mph, and make up nearly 30 percent of all tornadoes. They can last 20 minutes or more, and contribute up to 30 percent of all tornado deaths. Violent tornadoes can stay on the ground for more than an hour with winds in excess of 250 mph and are responsible for the majority of tornado fatalities. Most of the structural damage done during a tornado is due to the high wind speeds and the rubbish those winds toss around. For example, a strong or violent tornado can uproot objects as large as trees and send them flying fhrough the air like missiles. A brief tornado touchdown may leave as little as a few yards of damage. A big tornado that stays on the ground can leave a path of destruction over 50 miles. The 2007 tornado that destroyed 95 percent of Greensburg, Kansas was just under 2 miles wide and produced winds of 205 mph. 1. In what season(s) do tornadoes usually occur in the northern parts of the United States? _______________________________________________________________________________ 2. In what direction does the air spin to form a tornado? _______________________________________________________________________________ 3. What is a clear clue of a forthcoming tornado? _______________________________________________________________________________ 4. What are the three types of tornadoes? _______________________________________________________________________________ 5. What type of tornado accounted for the largest number of deaths? _______________________________________________________________________________ 6. What may cause the damage in a tornado? _______________________________________________________________________________ 7. What type was the tornado in 2007 classified into? _______________________________________________________________________________