Alberta Clipper - Effects

Effects

The storms sweep in at high speed over whatever land they encounter, usually bringing with them sharp cold fronts and drastically lower temperatures. It is not uncommon for an Alberta clipper to cause temperatures to drop by 16°C (30°F) in as little as 10 to 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 56 to 72 km/h (35 to 45 mph). These conditions would cause wind chill values to drop into the -30 to -45 Celsius (-20 to -50 Fahrenheit) range.

Snowfall amounts with these systems tend to be small (on the order of 1 to 3 inches or 2.5 to 7.5 cm), as the severe lack of moisture and quick movement inhibit substantial snowfall totals. However, several factors could combine to produce somewhat impressive snowfall totals (6 inches/15 cm or more). These factors include access to more moisture (which raises precipitation amounts), slower system movement (which increases snowfall duration), and colder temperatures (which increases the snow to water ratio). The southern and eastern shores of the Great Lakes often receive enhanced snowfall from Alberta clippers during the winter, due to lake enhancement. The lake-effect snow can add substantially to the overall snowfall total.

Occasionally the clippers, when reaching the Atlantic seaboard (usually between the Virginia and New England coasts), 'bomb out' and can cause severe winter weather along the coast as Atlantic moisture is tapped. Snowfall amounts can approach 6"-12" or more when this happens.

During the winter, Alberta clippers can occur somewhat frequently, with system intervals on the order of two to four days common during active periods.