A derecho is a widespread, long-lived, straight-line wind storm that is associated with a fast-moving group of severe thunderstorms known as a mesoscale convective system.
A shelf cloud along the leading edge of a derecho in Minnesota
Composite radar image of the June 2012 North American derecho (a progressive derecho) as it moved from Indiana to Virginia
A typical multi-bow serial derecho
A typical progressive derecho
Severe weather is any dangerous meteorological phenomenon with the potential to cause damage, serious social disruption, or loss of human life. Types of severe weather phenomena vary, depending on the latitude, altitude, topography, and atmospheric conditions. High winds, hail, excessive precipitation, and wildfires are forms and effects of severe weather, as are thunderstorms, downbursts, tornadoes, waterspouts, tropical cyclones, and extratropical cyclones. Regional and seasonal severe weather phenomena include blizzards (snowstorms), ice storms, and duststorms.
Various forms of severe weather
Panorama of a strong shelf cloud, which can precede the onset of high winds
The F5 tornado that struck Elie, Manitoba, Canada, in 2007
Formation of numerous waterspouts in the Great Lakes region
