It’s March which means tornadoes are going to be twisting into town within the next month.

According to the National Weather Service, Tennessee sees most of its tornadoes from March to May. During this time, the seasons are changing from the cold air of winter to the warm air of spring and summer. The mixture of cold and warm winds could end up forming tornadoes and causing major damage.

One of the most common natural disasters in the U.S., tornadoes cause an average of 80 deaths across the nation each year.

Here is what to know about tornado season.

How do tornadoes form?

The National Weather Service says that tornadoes are violently rotating columns of air that extend from a thunderstorm. They develop when wind variations support extreme rotation. While there is no clear-cut formula for developing a tornado, it is believed that the key ingredients for a tornado are warm, moist air near the ground with cooler dry air above.

Graphics: Here’s a look at how the storms form

What area of the country do tornadoes occur most?

According to the weather service, Arkansas, Louisiana, Oklahoma and Texas are the top states for tornadoes to occur in with Texas being No. 1. The most common month to see tornado activity is in April regardless of location.

The widest tornado ever recorded was in Oklahoma in 2013. The tornado had a width of 2.6 miles and was on the ground for 16.2 miles.

How many tornadoes occur in the U.S. each year?

According to the National Oceanic and Atmospheric Administration, about 1,200 tornadoes hit the U.S. yearly. The official tornado record didn’t start until 1950, so the average record is based on the last 70 years. In addition to this, the way we report and spot tornadoes has changed over the last several decades, so the numbers in more recent years are likely to be the most accurate.

More: Tornado ravages Wynne, Arkansas, leaves 4 dead, trail of debris, destruction

What is the scale for tornadoes?

Tornadoes are scaled based on the speed of the winds, not the width or height. The scale used for tornadoes is called The Enhanced Fujita Scale which has been in use since 2007. There are six total rankings

• EF-0: 65-85 mile per hour winds
• EF-1: 86-110 mile per hour winds
• EF-2: 111-135 mile per hour winds
• EF-3: 136-165 mile per hour winds
• EF-4: 166-200 mile per hour winds
• EF-5: >200 mile per hour winds

Do tornadoes happen in other countries?

According to the National Oceanic and Atmospheric Administration, tornadoes can occur on any continent except for Antarctica. Outside of the United States, the two countries with the highest concentration of tornadoes are Argentina and Bangladesh.

More: Ford’s BlueOval City partners to build temporary schools for Covington post-tornado

How to stay safe during a tornado?

The National Weather Service recommends different approaches to tornado safety based on your location when the tornado warning is issued.

When inside a home or small building, the weather service recommends:

• Going to the basement or the lowest level of the building.
• If there is no basement, go to a closet, bathroom or interior hallway away from any windows. The goal is to be in the center of the home or building.
• Use blankets, pillows, cushions, sleeping bags or mattresses to protect yourself from flying debris.

When in schools, hospitals, factories or shopping malls:

• Go to designated shelter areas.
• Stay away from windows.
• Kneel on the floor against the wall and place your hands over your head to protect against flying or falling debris.