A tornado is a small violent vortex. A derecho (pronounced deh-RAY-cho) is a widespread straight-line windstorm. Both can destroy homes and kill people, but they're fundamentally different phenomena. Confusion between them is common in the wake of major wind disasters.
| Feature | Tornado | Derecho |
|---|---|---|
| Structure | Rotating vortex | Straight-line winds |
| Size | 100 yards to 1 mile | 50-200 miles wide |
| Length | Yards to 200+ miles | 250+ miles minimum |
| Duration | Minutes to hours | 6+ hours |
| Wind speeds | 65-300+ mph | 58-130 mph typically |
| Parent storm | Supercell | Squall line/MCS |
| Damage pattern | Narrow, twisted debris | Wide, aligned debris |
The single best clue after a disaster is how debris is oriented:
A single tornado rarely exceeds 100 miles of continuous damage. A derecho typically produces damage over 250-1,000 miles.
Tornado supercells show hook echoes and mesocyclone signatures. Derechos appear as long bow echoes stretching across radar.
Individually, a violent tornado is far more dangerous than a derecho. Peak tornado winds exceed peak derecho winds by 2-3x. Tornadoes can lift and throw vehicles; derechos generally cannot.
But derechos affect much larger areas simultaneously - a single derecho may damage hundreds of thousands of homes across a multi-state region. Total derecho fatalities can rival small tornado outbreaks.
Yes. Derechos can spawn embedded tornadoes, especially at the leading edge. These tornadoes are typically brief (EF0-EF1) but can be strong. The 2012 Mid-Atlantic derecho produced multiple embedded tornadoes.
Conversely: a tornado outbreak day can also produce a derecho along the same squall line, especially in the evening as the storms consolidate.
The NWS added enhanced severe thunderstorm warnings in 2021 specifically to raise urgency around derecho events after several were under-warned.
For both tornadoes and derechos, the safety rule is the same: get into a well-built structure, interior room, lowest floor. But derechos have some unique risks: