Question submitted by Parris
(Singapore)
Meteorologically speaking a wind gust is defined as the maximum 3-second wind speed that occurs (or is forecast to occur) within a 2-minute interval at a height of 10 meters above ground.
A squall however is a non-frontal line or belt of violent convective activity, sometimes seen with vigorous thunderstorms. Forecasters use the term "squall line" to describe a sudden wind-speed increase of 8 metres per second (29 km/hr) or more, for one minute or longer. It includes several briefer wind-speed changes, or gusts.
A squall however, is often named for the weather phenomenon that accompanies it, such as rain, hail, or thunder; a line squall is one associated with a squall line of thunderstorms that is often hundreds of kilometres long.
In Ontario for example, lake effect snow squalls are common features seen downwind of open and relatively mild water, in a cold windy winter airmass. They are intense, but of limited spatial extent and duration, periods of moderate to heavy snowfall, accompanied by strong, gusty surface winds and possibly lightning. Snow accumulation may be significant in the squall.
Claire Martin is an award winning Senior Meteorologist for CBC News: Vancouver. She has over 20 years of experience ranging from official weather observing to operational forecasting to television broadcasting. She has worked for Environment Canada and the UK Meteorological Office in England. In 2005, Claire was awarded "Certified Broadcast Meteorologist" by the American Meteorological Society. The International Weather Festival awarded Claire Martin the honour of "Best Weather Presenter in the World" in 2000, 2001 and 2003.
