While storms that spawn tornadoes are thought of as being primarily a spring thing, because the majority of tornadoes occur from April through June. But the reality is that tornadoes can happen at any time of year. In fact, an F-2 tornado just ripped through an industrial park in Windsor, Ontario, Canada on August 25. If you live in a tornado zone, then how to survive a tornado is something you probably grew up preparing for. People visiting a tornado-prone area or just driving through, however, may not know what to do.

And, just because you don’t live in “tornado alley” is no reason to be complacent–tornadoes have touched down in all 50 states. In 2012, twin tornadoes touched down in Brooklyn and Queens in New York in September, with winds of about 70 mph. An F-4 tornado occurred at 10,000 feet in northwest Wyoming on July 21, 1987. Although that was a rare meteorological event, never assume that just because you’re at a high altitude that you don’t need to be aware of the weather. Tornadoes can occur whenever and wherever conditions are right.

Tornado ratings

Modern measurements use a system called the Enhanced Fujita Scale for rating the intensity of tornadoes. The scale is named after Dr. Ted Fujita, a storm scientist at the University of Chicago who developed the sale in 1971. The scale ranges from F-0 to F-5, with 5 being the most severe storm. Approximate wind speeds for each category range from 65 to 85 mph for F-0 to greater than 200 mph for F-5.

Damage That Can Be Expected
According to Weather.com, the following chart summarizes the damage that can be expected from a tornado at each level of intensity.

F-0
Wind speeds: 65 to 85 mph
Typical Observations: Light damage. Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over.

F-1
Wind speeds: 86 to 110 mph.
Typical Observations: Moderate damage. Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken.

F-2
Wind speeds: 111 to 135 mph.
Typical Observations: Considerable damage. Roofs torn off well-constructed houses; foundations of frame homes shifted; mobile homes completely destroyed; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground.

F-3
Wind speeds:136 to 165 mph.
Typical Observations: Severe damage. Entire stories of well-constructed houses destroyed; severe damage to large buildings such as shopping malls; trains overturned; trees debarked; heavy cars lifted off the ground and thrown; structures with weak foundations blown away some distance.

F-4
Wind speeds: 166 to 200 mph.
Typical Observations: Devastating damage. Whole frame houses Well-constructed houses and whole frame houses completely leveled; cars thrown and small missiles generated.

F-5
Wind speeds: more than 200 mph.
Typical Observations: Incredible damage. Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 m (109 yd); high-rise buildings have significant structural deformation; incredible phenomena will occur.

Characteristics

About 1,200 tornadoes hit the United States each year. The energy of a tornado is concentrated in a relatively small area perhaps only a hundred yards across. In the U.S. tornadoes are most common in the central plains of North America, east of the Rocky Mountains and west of the Appalachian Mountains. They also occur in other parts of the world. They usually occur during the late afternoon and early evening. Winds that reach 300 mph can rip homes to shreds and even strip asphalt from pavement, pick up cars like toy blocks and send dangerous objects like tree limbs flying through the air. Tornadoes can only be predicted to a limited extent. People describe the sound of a tornado as that of a very loud train or jet engine.

Tornadoes can occur whenever the surface temperature is much warmer than the air higher up. Warm air near the surface rises and carries with it condensation, which leads to clouds and thunderstorms. If the winds are right, a tornado is possible.

Learn how to recognize the cloud formations and weather conditions that are likely to lead to tornadoes. These are wall clouds, although a wall cloud is not always present. You may also not be able to see a wall cloud depending on your angle of view. A wall cloud is a cloud that forms below a thunderstorm cloud and abruptly lowers.  A funnel cloud often extends from the base of a cloud and looks like a rotating cone. If the funnel cloud touches the ground it becomes a tornado. However, some tornadoes may not have a funnel cloud.

Tornado Watches and Tornado Warnings

A “tornado watch” means severe, tornado-producing weather is possible over a period of a few hours. You need to be alert, and be prepared to seek shelter if tornadoes happen or a warning is issued. A “tornado warning” means that a tornado has been spotted, or that Doppler radar shows a thunderstorm circulation which can spawn a tornado. When a tornado warning is issued for your area, seek safe shelter immediately.

How to Survive a Tornado

Tornadoes travel at around 10 to 20 mph, even if their wind speed is much greater than that. Outrunning on one foot is not possible, but in a car, if you have advance warning that it’s coming, you have a chance. Try and gauge the tornado’s movement and direction and drive away only if you’re sure the tornado is not coming towards you. Drive away at a right angle to the direction the tornado is moving–in other words, in a direction that puts the most distance between you and the tornado.

If you’re stuck in a car,  the Red Cross recommends getting off the road, parking the car, and slouching down low in your seat while still keeping your seat belt on. Lean away from the windows and cover your head with something to keep broken glass off you.

Seek strong shelter or at least take some cover like covering yourself with a mattress or a sturdy desk. The biggest danger is flying debris. If you’re in a house or building with a basement, go there. Some buildings may have storm shelters. Use them. If you aren’t sure where to go, go to an interior room or bathroom, far from windows. Crouch, covering your head and face.

If you’re outside, like flat on the ground or in a ditch. Try to pick a spot away from trees and buildings. If you’re driving, consider getting out of your car and running to safe place, because a twister can easily pick up a car and throw it like it’s nothing. Trying to get under and overpass or bridge is not a good idea, either. A tornado could collapse the bridge.