​A tornado appears as a rotating, funnel-shaped cloud that extends from a thunderstorm to the ground with whirling winds that can reach 300 miles per hour. Damage paths can be in excess of one mile wide and 50 miles long. Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others. Occasionally, tornadoes develop so rapidly that little, if any, advance warning is possible. Before a tornado hits, the wind may die down and the air may become very still. However, some tornadoes can have winds of 200 mph or more. A cloud of debris can mark the location of a tornado even if a funnel is not visible. Tornadoes generally occur near the trailing edge of a thunderstorm.

Maryland usually receives at lease several tornadoes a year. Many hit in sparsely populated rural areas and cause little or damage or casualties. In Maryland, notable tornadoes have caused casualties and/or significant damage in LaPlata and the College Park-Beltsville-Calverton area. The most common time of year for tornadoes to occur in Maryland is April through November, and most occur between 3 p.m. and 9 p.m.

Before an Emergency

• ​Build an emergency kit and create a family communications plan.
• Look for the following danger signs:
• Dark, greenish sky
• Large hail
• A large, dark, low-lying cloud
• Loud roar, similar to a freight train
• If you see approaching storms or any of the danger signs, be prepared to take shelter immediately.

During an Emergency

• In a high-rise building go to a small interior room or hallway on the lowest floor possible.
• Do not open windows
• If you live in a mobile home, get out immediately and go to the lowest floor of a sturdy, nearby building or storm shelter.
• If you are outside with no shelter
• Immediately get into a vehicle, buckle your seat belt and try to drive to the closest sturdy shelter.
• Never try to outrun a tornado in urban or congested areas in a car or truck. Instead, leave the vehicle immediately for safe shelter.
• Watch out for flying debris. Flying debris from tornadoes causes most fatalities and injuries.

After​ an Emergency​​

• ​Continue to monitor your battery-powered radio or television for emergency information.
• Be careful when entering any structure that has been damaged.
• Wear sturdy shoes or boots, long sleeves, and gloves when handling or walking on or near debris.
• Be aware of hazards from exposed nails and broken glass.
• Do not touch downed power lines or objects in contact with downed lines. Report electrical hazards to the police and the utility company.
• Use battery-powered lanterns, if possible, rather than candles to light homes without electrical power.
• Be aware of possible structural, electrical or gas-leak hazards in your home.
• In general, if you suspect any damage to your home, shut off electrical power, natural gas and propane tanks to avoid fire, electrocution or explosions.
• If you smell gas or suspect a leak, turn off the main gas valve, open all windows and leave the house immediately. Notify the gas company, the police or fire departments, or State Fire Marshal's office and do not turn on the lights, light matches, smoke or do anything that could cause a spark.
• Do not return to your house until you are told it is safe to do so.