We'll start with the most urgent -- a tornado warning.
If there's a warning, it means a tornado has been spotted and it's time to take cover -- it's too late for you to develop a plan, according to CNN Meteorologist Chad Myers.
• If you're near a well-built structure (no mobile homes or temporary buildings), check if it has a safe room and use that. If there's no safe room, go to the basement. If there's no basement, go to a room in the centermost part of the building on the ground floor. You're looking for something that puts as many walls in between you and the storm and has no windows. Try to hide under something sturdy (a hard desk) and protect your head and neck. Be aware of what's above you if you're in a multi-story building (like a refrigerator that could fall on you).
• If you're in a mobile home or temporary structure, get out and find something more stable.
• If you're outside (or in a mobile home with nothing nearby), look for a permanent shelter nearby. If there is none, you should always avoid going under overpasses or bridges (they can create wind tunnels).
A tornado watch means that a tornado could strike that day.
It's not enough time to build a safe room or a basement (FEMA has tips for that
if you're interested), but it's enough time to get a plan in place.
Still, make sure you follow the latest developments (the National Weather Service, your local news and these apps
are helpful places to start) so you know when one does hit.
You should have an emergency kit ready that includes anything you'd need if you were to survive 72 hours disconnected from the world.
Make sure you have non-perishable food (try to avoid things that make you thirsty -- FEMA recommends
salt-free crackers, whole grain cereals and canned foods with high liquid content), water (a gallon per person per day) and prescription medications you or family members take. A helmet might also be useful.
FEMA has a longer, more comprehensive list
if you've got time to prepare a fully-loaded kit.
Make sure you also have a way to get in touch with family and friends. Just in case phones and computers aren't available, set a designated meeting point with those close to you to let them know you're OK after the storm.
Last, but certainly not least: Just because you live in a state where tornadoes are rare, or it's not "tornado season," it's best not to let up. Tornadoes can form in every state, and have been known to wreak devastation even in perceived off months.
To run or not to run?
While the most common advice is to shelter in place, some experts say it may sometimes be smart to run.
DHS does not specify whether you should run in the event of a tornado warning, but does list driving to the closest shelter as an "possible action" if you're outside with no shelter during a tornado.
If you are going to try to outrun it, travel perpendicular from the direction you think the tornado is going, says Ed Bates, an architect who designs buildings that incorporate storm shelters.
Ernst Kiesling, a civil engineering professor at Texas Tech University who has spent his life studying tornadoes and developing above-ground storm shelters to protect against them, says it's a "tough question."
"My advice would be to seek the safest place available. That is: lie in a ditch or ... (get) behind a heavy object if you had a tractor or even a tree."
He cited the 1979 Wichita Falls, Texas, tornado as a cautionary lesson. That twister killed 54 people and, Kiesling noted, "many people were killed in automobiles because they tried to outrun it."
Still, Kiesling allowed, there may be times when fleeing an impending tornado might be a good option.
"If you have good information on the storm, if you have plenty of warning, if you have an automobile, it may make sense, but I personally don't feel that's the advice that we want to give the public."
Work with what you've got
There's a good chance that if a tornado approaches, you might not be near a storm shelter or a basement or your emergency kit, so it's important to use what you have at the time of the impact to increase your survival chances.
Emergency room doctors at Moore Medical Center pulled mattresses and blankets off hospital gurneys and used them to cover themselves
and their patients as the tornado approached.
Those simple actions might have saved lives as the tornado wiped out the hospital's second floor.
Workers and customers at a credit union got inside the bank vault
, which proved to be the only thing standing after the tornado reduced the rest of the building to rubble.
The tornado wiped out the school and many sustained serious injuries, but everyone survived.