A derecho is a widespread and long-lived windstorm that is associated with a fast-moving band of severe thunderstorms.
They can produce significant damage to property and pose a serious threat life, primarily by downburst winds.
To be classified as a derecho, the path length of the storm has to be at least 280 miles long, but the widths may vary from 50-300 miles.
Derechos are usually not associated with a cold front, but a stationary front.
They occur mostly in July, but can occur at anytime during the spring and summer.