According to the National Oceanic and Atmospheric Administration (NOAA), tornadoes come in all shapes and sizes and can occur anywhere in the U.S. at any time of the year. In the southern states, peak tornado season is March through May, while peak months in the northern states are during the summer.
The following resources from U.S. Government agencies and nonprofit organizations can help you deal with this type of emergency.
Advice on what you should do during a tornado and ways to seek shelter
What you should know to deal with safety issues after a tornado, especially if there is also flooding or dealing with debris
(Centers for Disease Control)
Advice about keeping drinking water and food safe for consumption
(Environmental Protection Agency)
Advice on what to do before, during and after a tornado
(American Red Cross)