What is a tornado? A tornado is defined as a violently rotating column of air descending from a thunderstorm cloud to the ground. It nearly always starts as a funnel-shaped rotating extension from a thunderstorm cloud, building downward to the ground and grows dark as it picks up debris. The most violent tornadoes are capable of remarkable destruction with wind speeds of 250 mph or more. Damaging paths can be in excess of one mile wide and 50 miles long.
Under what conditions do most tornadoes occur? Tornadoes form several thousand feet above the earth’s surface, usually during warm, humid, unsettled weather, and usually in combination with a severe thunderstorm. They require the presence of layers of air with contrasting characteristics of temperature, moisture, density, and wind flow.
During what time of day are tornadoes most likely to develop? Tornadoes are most likely to occur at mid-afternoon, generally between 3 and 7 p.m., but they have occurred at all times of the day.
What direction does a tornado move? Usually from southwest to northeast.
What is the length of a tornado’s path? Tornadoes generally average about 4 miles but may reach 300 miles.
How wide is a tornado’s path? It averages about 300 to 400 yards, but tornadoes have cut strips a mile and more in width.
How fast do they travel? Average speed of a tornado is from 25 to 40 miles per hour, but speeds ranging from stationary to 68 miles per hour have been reported.
Is it true that if it rains there is no chance of a tornado? No!! Precipitation associated with the tornado usually occurs first as rain just preceding the storm, frequently with hail, and as a heavy downpour immediately to the left of the tornado’s path.
Can you hear a tornado? DEFINITELY YES! A tornado has been described as a roaring, rushing noise, closely resembling that made by a train speeding through a tunnel or over a trestle, or the roar of many airplanes.
What is meant by a “tornado watch”? A “watch” indicates an area in which atmospheric weather conditions exist from which a tornado could develop. Tornado “watch” bulletins always state that severe thunderstorm activity is also expected. A severe thunderstorm is one containing either damaging winds (surface gusts greater than 75 miles per hour) or hailstones at least 3/4 inch in diameter at the surface of the ground or both.
What is meant by a “tornado warning” or “severe thunderstorm warning”? A “warning” is issued when a tornado or severe thunderstorm has been sighted in the area by severe weather spotters or radar.