Weather Wednesday: Arctic Clipper

Rick Atterberry, EDEN Immediate Past Chair writes about the weather. 

What’s with Weather Wednesdays?   Well, when my term as chair of the Extension Disaster Education Network came to an end in October of 2014, Virginia White asked me if I’d write an occasional blog post for EDEN and our eXtension Community of Practice.

Ever since I wrote a series of posts during and after the response to tornadoes in November of 2013 that affected Gifford, Illinois, which is in Champaign County where I serve as the volunteer Emergency Management Agency Public Information Officer and Washington, Illinois, where I grew up and have many family and friends, I’d been thinking about writing about the weather more regularly.

I hasten to add I am not a meteorologist.  Indeed we do have an actual meteorologist or two in EDEN, including Tom Priddy at the University of Kentucky who created our terrific Next 48 online dashboard tool.  I do have some formal training, but will, as any Extension employee would, rely on research.  Often, I’ll write about threats and best-practices.  On the other hand, some musings may be weather related, but not all that technical.

If you have topics you’d like to see addressed, let me know at ratterbe@illinois.edu .  In the meantime, I hope you’ll enjoy this post about the dreaded “Alberta Clipper.”

What’s an Alberta Clipper?

Much of the continental United States occasionally shivers through a winter weather system known as an Alberta Clipper.  In fact, the first full week of January this year was a classic example with record and near record low temperatures in many areas east of the Rockies.

An Alberta Clipper is a low pressure area that generally originates on the lee side of the Rockies in Alberta, but can also start in Saskatchewan or even Montana.  The “clipper” part is considered a reference to the speeds of the clipper ships. As the cold air is caught up in the typical winter jet stream pattern, it can be pushed far south in the U.S.

Alberta Clippers are characterized by sometimes dramatically colder temperatures resulting in the temperature dropping 20 degrees or more in a relatively short time.  While there is snow associated with most clipper systems, it is usually light, maybe one to three inches, and often with very low moisture content so it is easily blown about by the high winds that may occur.  It is not unusual for an Alberta Clipper to result in a “ground blizzard” after the snowfall has ended.   A ground blizzard results when snow already on the ground or falling as post-frontal flurries is caught up in the wind making forward visibility difficult and resulting in snow drifts and icy patches on highways as was experienced recently.  During a ground blizzard it is often possible to look up and see the sky much more clearly than one can see forward.

While snowfall is limited in a clipper system, the colder temperatures can plunge far south which is certainly what happened this past week.  Some of the coldest weather experienced each winter is often associated with clippers and wind chills can typically reach 30 to 40 degrees below zero, or lower, in the North Central, Great Lakes and North Atlantic States.

Threats associated with clippers include difficult driving conditions; frostbite; frozen pipes; slips and falls; residential fires resulting from malfunctioning or improperly used furnaces, fireplaces and auxiliary heating appliances; cold weather hazards to pets and livestock; and mechanical difficulties with outdoor machinery.