An Alberta clipper (also known as a Canadian Clipper) is a fast-moving low-pressure area that generally affects the central provinces of Canada and parts of the Upper Midwest and Great Lakes regions of the United States. Most clippers occur between December and February, but can also occur occasionally in the month of November. Alberta clippers take their name from Alberta, Canada, the province from which they appear to descend, and from 19-century clipper ships, one of the fastest sailing ships of that time.
It is not uncommon for an Alberta clipper to cause temperatures to drop by 30°F (16°C) in as little as 10–12 hours. Often, the storms bring biting winds with them, only increasing the effect of the newly lower temperatures. Winds in advance of and during an Alberta clipper are frequently as high as 35–45 mph (56–72 km/h). These conditions would cause wind chill values to drop into the –20 to –50°F (–30 to –45°C) range.
Two variations of Alberta clippers are Manitoba Maulers and Saskatchewan Screamers. These two types of systems are far less common than clippers, and even when they take place they are still often referred to as clippers. The main difference between the three is the Canadian province from which they begin their southward trek.
14 January 2009
Apropos of our current weather, I’ve been seeing the term “Alberta clipper” all over the weather sites, and the name sounds so romantic to me, bringing to mind images of a ghostly white ship out of Canada crewed by pirate ghosts with frosty, wind-whipped beards (all right, so maybe I’ve had too much coffee this morning).