Most storm chasers use regular vehicles to chase, and obviously, they don't try to get too close to the tornado. But when they get important information like damage descriptions, wind speeds, size, etc, they notify the NWS. Once the National Weather Service receives the information, they try to notify civilians and update them as soon as possible. This is how you get what we know today as "Tornado watches" or even "Tornado warnings."

EF-0 Damage rips off roof shingles, knocks over trash cans, throws tree branches, and might cause little damage to cars; however, any type of tornado caused by a supercell thunderstorm is highly dangerous.

EF-1 Damage can break larger branches off of trees, break windows, slam poorly locked doors open, and cause damage to garage doors. Think of it as the EF-0's angry teenager.

 Now we are getting serious. Walls can fall, trees can be snapped, cars can flip over, roofs can be lifted off, and wooden beams can fall, making more parts of the house collapse due to being unsupported.

EF 3 tornado damage can loft cars, smash and collapse houses, throw trees like nothing, knock over mobile homes, and even send debris flying for miles.

EF 4 tornadoes can make houses collapse in seconds with no walls standing. They can throw heavy cars and mobile homes like toddlers throwing toys. Nothing but a debris-filled landscape.

EF5 Tornadoes are so strong that they can lift commercial planes easily, rip open underground cellars or basements, show only the foundation of houses, and send anything flying like toys.