What is the difference between a derecho and a squall line?

Derechos and squall lines are both types of weather events that can produce damaging winds, but they differ in their structure and formation. A squall line is a narrow band of thunderstorms that can extend for hundreds of miles and typically forms ahead of a cold front. It is often characterized by a line of intense thunderstorms with a bow-shaped echo on radar.

Derechos, on the other hand, are more organized and long-lived events that are associated with a widespread and long-lasting wind damage. Derechos are typically formed by a large, mesoscale convective system (MCS) that can cover an area of hundreds of miles and can produce wind gusts over 58 mph. Unlike squall lines, derechos are associated with straight-line winds that can cause significant damage to property and infrastructure.

In summary, while both derechos and squall lines can produce severe weather and damaging winds, the main difference between them lies in their structure and formation. Squall lines are narrow bands of thunderstorms that form ahead of a cold front, while derechos are more organized and long-lived events that are formed by a large, mesoscale convective system.