Severe Summer Weather Terms: Squall Lines, Microbursts, and Derechoes
A glossary of meteorological terms explaining severe convective summer storms in Canada.
Key Summer Storm Terms
Summer in Canada brings severe convective storms. Here is a glossary of terms used by meteorologists:
Squall Line (Ligne de grain)
A narrow band of active thunderstorms, often developing ahead of a cold front, characterized by wind gusts, hail, and torrential rains.
Microburst (Rafale descendante)
An intense, localized column of sinking air (downdraft) within a thunderstorm. When it hits the ground, it spreads out in all directions, creating damaging straight-line winds of up to 150 km/h, which are often mistaken for tornadoes.
Derecho (Derecho)
A widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. By definition, a derecho must cause wind damage extending over a swath of at least 400 kilometers.
