Tornadoes are violent, destructive storms that wreak havoc and devastation across their paths. Although every tornado will not display the same warning signs before it occurs, certain weather patterns and activities point toward a tornado forming or approaching. High winds don't always mean a tornado; a signal could be just the opposite weather conditions. Meteorologists use the telltale signs to forecast the probability of a tornado forming.
Before a tornado actually appears or arrives, hail usually tumbles to the ground. The hail is often the size of golf balls but may be smaller. Before the tornado inflicts its damage, initial damage is often done by hail striking roofs and other parts of houses, vehicles and street signs. A thunderstorm that produces hail does not always signal a tornado; it is just an event that often accompanies a tornado's appearance. It could also simply be a hailstorm.
A tornado is the definition of violent energy unleashed. Many times, instead of the continual high winds that you might expect to be in the air, indicating a tornado's impending approach, the air instead becomes eerily calm, still, motionless. If you gaze around, you won't notice the tops of trees swaying, or debris zipping past you. There is no whistling breeze, only a silence that is noticeably void of any discernible character or movement.
Green Sky and Train Sound
In addition to growing darker, the sky often takes on a greenish color. While by itself, a green sky does not always signal that a tornado is approaching, its occurrence is a signal to be vigilant against a possible tornado. The dark sky, shrouded by swirling debris, that surrounds a moving tornado may also be very near a sky that displays sunshine. In contrast to a green sky, a loud roar that resembles a fast-approaching freight train is usually a clear, very disturbing signal that a tornado is indeed approaching.
Local authorities exert extreme efforts to notify citizens when the formation of a tornado is possible and when a tornado is definitely approaching. Hearing blaring storm sirens are a major way for area inhabitants, especially those who are outside, to learn that a tornado is about to strike. When you hear these sirens, which are normally installed at strategic community locations, immediately seek interior shelter. If you are already inside, turn to a local station on the television or radio to hear any weather bulletins. Although a tornado watch means conditions are favorable for a tornado, a tornado warning means an actual tornado has been visually sighted or has been indicated on radar, and may hit within the areas covered in the warning.