A derecho is a widespread, long-lived windstorm associated with a fast-moving complex of severe thunderstorms known as a mesoscale convective system. It produces powerful straight-line winds that can cause hurricane-force gusts, heavy rain, and flash floods over a large area, often hundreds of miles long. Key characteristics of a derecho include:
- Winds that exceed 58 mph (about 93 km/h), sometimes reaching over 100 mph.
- A damage path that extends more than 240 miles (about 400 km) long and at least 60 miles (about 100 km) wide.
- The winds move in a straight line, unlike tornadoes which have rotating winds, which is where the name "derecho" (Spanish for "straight") comes from.
- They often form bow-shaped radar echoes known as bow echoes.
- Derechos mainly occur in warm weather, typically during summer months, although they can happen at any time of the year.
- They cause damage comparable to tornadoes and hurricanes but cover a much larger area with straight-line winds.
Derechos are sometimes called "inland hurricanes" due to their powerful winds and widespread destruction but differ in formation and wind behavior from hurricanes. In summary, a derecho is a fast-moving storm system of severe thunderstorms that produces long-lasting, expansive straight-line winds causing substantial wind damage across wide regions. They are rare but can be extremely destructive when they occur. This definition is supported by information from meteorological sources including NOAA, the National Weather Service, and weather science explanations.
