Alberta clipper
Encyclopedia
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
which generally affects the central provinces
Provinces and territories of Canada
The provinces and territories of Canada combine to make up the world's second-largest country by area. There are ten provinces and three territories...
of Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
and parts of the Upper Midwest
Upper Midwest
The Upper Midwest is a region in the northern portion of the U.S. Census Bureau's Midwestern United States. It is largely a sub-region of the midwest. Although there are no uniformly agreed-upon boundaries, the region is most commonly used to refer to the states of Minnesota, Wisconsin, and...
and Great Lakes
Great Lakes region (North America)
The Great Lakes region of North America, occasionally known as the Third Coast or the Fresh Coast , includes the eight U.S. states of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin as well as the Canadian province of Ontario...
regions of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Most clippers occur between December and February, but can also occur occasionally in the month of November. Alberta clippers take their name from Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, the province from which they appear to descend, and from clipper ships
Clipper
A clipper was a very fast sailing ship of the 19th century that had three or more masts and a square rig. They were generally narrow for their length, could carry limited bulk freight, small by later 19th century standards, and had a large total sail area...
of the 19th century, one of the fastest ships of that time.
Formation
A clipper originates when warm, moist winds from the Pacific OceanPacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
come into contact with the mountains in the provinces of British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
and then Alberta. The air travels down the lee side
Windward and leeward
Windward is the direction upwind from the point of reference. Leeward is the direction downwind from the point of reference. The side of a ship that is towards the leeward is its lee side. If the vessel is heeling under the pressure of the wind, this will be the "lower side"...
of the mountains, often forming a chinook
Chinook wind
Chinook winds , often called chinooks, commonly refers to foehn winds in the interior West of North America, where the Canadian Prairies and Great Plains meet various mountain ranges, although the original usage is in reference to wet, warm coastal winds in the Pacific Northwest.Chinook is claimed...
in Alberta, then develops into a storm over the Canadian prairies when it becomes entangled with the cold air mass
Air mass
In meteorology, an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of square miles, and adopt the characteristics of the surface below them. They are classified according to latitude and their continental or maritime...
that normally occupies the region in winter. The storm then slides southward and gets caught up in the jet stream, sending the storm barreling into central and eastern areas of North America.
Ironically, the chinook which in part originates the Alberta clipper usually brings relatively warm weather (often approaching 10C/50F in the depths of winter) to southern Alberta itself, and the term is therefore not used in Alberta.
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 chillWind chill
Wind chill is the felt air temperature on exposed skin due to wind. The wind chill temperature is always lower than the air temperature, and the windchill is undefined at the higher temps...
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
Bomb (meteorology)
Bomb is a meteorological term for a baroclinic low pressure area characterized by a rapid pressure fall of at least 24 millibars in 24 hours. It is applied only to cold-air storms...
' 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.
Variations
Two variations of Alberta clippers are Manitoba mauler or Saskatchewan screamer. 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 among the three is from which Canadian province they begin their southward trek.In popular culture
In the mid-1990s, Former Minnesota VikingsMinnesota Vikings
The Minnesota Vikings are a professional American football team based in Minneapolis, Minnesota. The Vikings joined the National Football League as an expansion team in 1960...
head coach Dennis Green
Dennis Green
Dennis "Denny" Green is an American football head coach for the Sacramento Mountain Lions of the United Football League...
erroneously referred to an Alberta Clipper as a "Calcutta Clipper" when talking about weather patterns that would have affected his teams preparation for an upcoming game.
See also
- SnowsquallSnowsquallA snowsquall is a sudden moderately heavy snow fall with blowing snow and strong, gusty surface winds. It is often referred to as a whiteout and is similar to a blizzard but is localized in time or in space and snow accumulations may or may not be significant.-Lake effect snow:When arctic air...
- Ground blizzardGround blizzardGround blizzard refers to a weather condition where loose snow or ice on the ground is lifted and blown by strong winds. The primary difference between a ground blizzard as opposed to a regular blizzard is that in a ground blizzard no precipitation is produced at the time, but rather all the...
- Windchill
North American weather patterns:
- Colorado lowColorado lowA Colorado low is a low pressure storm that forms in southeastern Colorado or northeastern New Mexico, typically in the winter. After forming, the system moves across the Great Plains. Colorado lows produce heavy wintry precipitation, and they have a general east to northeast movement, impacting...
- Nor'easterNor'easterA nor'easter is a type of macro-scale storm along the East Coast of the United States and Atlantic Canada, so named because the storm travels to the northeast from the south and the winds come from the northeast, especially in the coastal areas of the Northeastern United States and Atlantic Canada...
- Panhandle hookPanhandle hookA Panhandle hook is a relatively infrequent storm system whose cyclogenesis occurs in the South to southwestern United States from the late fall through winter and into the early spring months...
Further reading
- Williams, Jack: The Weather Book, 1997, Vintage Books, ISBN 0-679-77665-6.
- Dunlop, Storm: The Weather Identification Handbook: The Ultimate Guide for Weather Watchers, 2003, The Lyons Press, ISBN 1585748579.
External links
- Extratropical Lows: Clippers Meteorology Department of the University of IllinoisUniversity of Illinois at Urbana-ChampaignThe University of Illinois at Urbana–Champaign is a large public research-intensive university in the state of Illinois, United States. It is the flagship campus of the University of Illinois system...