Derecho vs. Tornado
Both can produce winds over 100 mph. Both can flatten buildings and snap trees. But a derecho and a tornado are fundamentally different storms — and the danger they pose is different too.
What Is a Derecho?
A derecho (deh-RAY-cho) is a widespread, long-lived windstorm associated with a fast-moving band of severe thunderstorms. To officially qualify as a derecho, the swath of wind damage must extend at least 250 miles with wind gusts of 58 mph or greater along most of its length.
Derechos produce straight-line winds — the wind blows in one direction, unlike a tornado's rotation. But those winds can reach 80–130 mph over a path hundreds of miles long and tens of miles wide, flattening everything in their way.
The June 2012 derecho hit from Indiana to the mid-Atlantic coast, leaving 4.2 million people without power. The August 2020 Midwest derecho caused $11 billion in damage across Iowa in under an hour.
Key Differences
Wind Direction
Tornado: Rotating winds spiral inward. Damage is twisted and scattered in different directions.
Derecho: Straight-line winds. Trees and structures fall in the same direction.
Size of Damage Path
Tornado: Narrow path, typically 100 yards to a mile wide, up to a few dozen miles long.
Derecho: 50–100+ miles wide and 250–500+ miles long. A single event can affect multiple states.
Duration
Tornado: Most last 10–20 minutes on the ground. Even long-track tornadoes rarely exceed an hour.
Derecho: The storm system can last 6–12+ hours as it races across hundreds of miles. The wind at any one location lasts 10–30 minutes.
Alerts
Tornado: NWS issues a Tornado Warning with a specific polygon.
Derecho: Severe Thunderstorm Warnings with "destructive" damage tags and/or Tornado Warnings for embedded rotation. There is no "Derecho Warning" — the NWS warns for each cell individually.
Why Derechos Are Underestimated
No Dedicated Warning
People hear "severe thunderstorm" and think rain and lightning. A derecho-producing line can be catastrophic, but the warning language doesn't always convey the severity.
They Move Fast
Derechos travel at 50–70 mph. By the time you see the shelf cloud on the horizon, you may have 10–15 minutes before 100 mph winds arrive.
Trees Are the Killer
Most derecho fatalities come from trees falling on cars, homes, and people. The wider damage path means far more trees affected than a typical tornado.
Stay Ahead of Both
StormCast delivers all NWS severe thunderstorm and tornado warnings to your phone within moments. Whether it's a supercell tornado or a derecho, you'll know before it arrives.
