The tornado that ripped through Moore, Oklahoma has left many questioning what they thought they knew about how the powerful natural disasters.
Here are the most common tornado myths debunked by the National Weather Service.
Myth: Tornadoes don't cross rivers. Although some landforms may influence the distribution of tornadoes, rivers do not have any clear effect on them.
The great Tri-State tornado of 1925, the deadliest tornado ever recorded, crossed both the Mississippi and the Wabash Rivers.
Myth: Open windows in your house to equalize pressure. Do not do this! Your house will not "explode" due to a tornado passing over it, and taking time to open windows merely reduces your ability to seek safe shelter in time.
Myth: Get to (or away from) the southwest corner of the building for safety. Of course, the safest place to be is in an underground storm shelter, or a reinforced above-ground storm shelter.
If neither is available, then the safest place in a building is in a small, reinforced room (such as a bathroom or closet) near the center of the building, on the lowest floor (preferably below ground).
Myth: During tornadoes, drivers should shelter under overpasses. Wind can actually accelerate under the overpass. And climbing an overpass is definitely not a good idea, since being up in the air could make someone more likely to get hit by windblown debris.
Myth: Tornadoes "skip." Sometimes, the damage path of a tornado will result in demolition of several buildings, followed by several lightly damaged, followed by several more demolished. This gives the impression that the tornado "skipped" over the less-damaged structures.
There are several possible explanations for what appears to be "skipping." One is that the surviving buildings were simply better-constructed. Also possible is that the orientation of the buildings resulted in varying degrees of vulnerability to the winds of the tornado. Finally, small eddies in the tornado's circulation can add or detract from the overall flow in the tornado's circulation.
Myth: Mobile homes attract tornadoes. This myth probably came from the tendency of tornadoes to demolish mobile homes while leaving nearby structures only slightly damaged.
Mobile homes can be severely damaged even by weak tornadoes, which tend to cause only minor damage to most other kinds of dwellings. If the mobile home is not tied down, it is vulnerable even to the winds of a not-quite severe thunderstorm, since such a building can be flipped over by winds around 50 mph.