Some of these have been passed down for a hundred years. Some killed people. Here's what's actually true.
Houses aren't sealed — air already leaks in and out fast enough to equalize any pressure change. Tornado damage comes from wind, not pressure. Opening windows wastes precious seconds and lets in flying debris. Ignore this myth entirely.
Overpasses are actually dangerous. They funnel wind, accelerating it. There's no protection from debris. Multiple people died sheltering under overpasses in the 1999 Oklahoma outbreak. If you're on the road and can't reach a building, abandon the vehicle and lie flat in a low ditch away from vehicles and trees.
Tornadoes don't reliably move in one direction, and debris ricochets. The safest spot in a basement is under a sturdy piece of furniture like a workbench, away from windows, and — if possible — in an area that isn't directly under something heavy on the upper floor that could fall.
Tornadoes have hit downtown Dallas, St. Louis (multiple times), Atlanta, Nashville, Salt Lake City, Miami, and many others. Cities cover a tiny fraction of Tornado Alley, so the statistical odds are lower — but "never" is completely wrong. If a supercell tracks through your city, you're just as vulnerable as anyone else.
Tornadoes cross rivers routinely, including the Mississippi, Ohio, Missouri and Cumberland. They cross mountain ridges too — the 1974 Super Outbreak had tornadoes climb across the Appalachians. Terrain has minor effects but does not stop a well-organized supercell.
Green skies indicate a lot of large hail suspended in the storm, which is a sign of a very strong thunderstorm — but not specifically a tornado. Green sky = seek shelter is fine advice, just not specifically tornado-focused.
If you have time to drive away safely (tornado is miles off and you know the road), fine — that's the best option. But if a tornado is close and you can't outrun it, a car is dangerous. Get to a substantial building, or as a last resort, abandon the vehicle and lie flat in a low area away from trees and other vehicles.
Most Plains tornadoes do move northeast, because that's the typical mid-latitude storm motion. But tornadoes routinely take unpredictable turns, right-move away from the parent storm, or move southeast in certain wind regimes. Don't rely on direction of approach to know where to shelter.
Mobile homes are the deadliest place in a tornado. 40+ percent of tornado fatalities happen in mobile homes despite them being a fraction of housing. Taping windows does nothing. If you live in a mobile home and a warning is issued, evacuate to a designated shelter or a substantial building. Every mobile home park in tornado country should have an accessible shelter plan.
December, January and February all produce significant US tornadoes, especially in the Southeast. Cool-season "QLCS" tornadoes are common along cold fronts. Any month can produce tornadoes if the atmospheric ingredients line up.
Hail indicates a strong thunderstorm updraft, which is a prerequisite for a supercell. But most severe hail storms don't produce tornadoes. Hail alone isn't a tornado signal — but it should tell you to check the radar and the sky.
Damaging straight-line winds, especially from a downburst or derecho, sound very similar to a tornado. If you hear the sound of a freight train and there's a warning out, treat it as a tornado. If it's a Severe Thunderstorm Warning without a tornado warning, it could be a downburst — the shelter response is essentially the same.
Sirens are meant for people outdoors, so they're often not audible indoors, especially at night with windows closed. Some communities don't have sirens. Some tornadoes strike before a warning is issued. A NOAA weather radio (or the FEMA Wireless Emergency Alerts on your phone) is a more reliable way to be woken up by a warning.
Larger tornadoes can produce a temporary lull between passing bands or vortices, and multi-vortex tornadoes can hit twice from the same parent storm. Stay in shelter until the NWS explicitly cancels the warning or you can confirm the storm has moved miles away.
Average tornado warning lead time went from 3 minutes in the 1980s to 13-14 minutes today. False alarm ratios are dropping. High-resolution models like the HRRR, Warn-on-Forecast, and mobile Doppler research all continue to improve forecasting. Progress is slow but real.