Types of heavy snow events which impact Pennsylvania
Winter Weather Preparedness Week continues with a discussion on the types of heavy snow events which impact Pennsylvania.
Pennsylvania experiences some of the worst winters, which can paralyze cities, stranding commuters, closing nearby airports, stopping the flow of supplies, and disrupting emergency and medical services. Heavy snow and significant accumulations can cause roofs to cave and can knock down trees and power lines. Economic impacts can be significant on cities and towns. Costs can add up for snow removal, repairing damages and the loss of business.
There a few ways the area can receive snow. Heavy snow can be produced 3 ways. Lesser snow amounts accompanying Alberta Clippers.
Nor’easters are intense areas of low pressure that typically develop along the eastern seaboard. They usually bring strong northeast winds and move along the coast. Snowfall rates can reach 2 to 4 inches per hour and last for several hours.
Overrunning can also produce heavy snow. This occurs when warm air aloft flows over colder air near the surface. The contrast of air masses is greatest during the winter season causing. Overrunning occurs most often when a large dome of high pressure is located in southeastern Canada and a warm front is approaching our region for the south or southwest.
Blizzards are another heavy snow producer. Some of the greatest snowfalls on record occurred during blizzards. Winds can exceed 35mph causing considerable blowing snow reducing visibility to at or below one-quarter of a mile.
An Alberta Clipper is an area of low pressure that usually develops over the province of Alberta in Canada, east of the Rocky Mountains. They usually move very quickly southeast across the northern tier of the United States through the Great Lakes into our region. They usually bring light snow once they swing through our area. They can intensify off the coast causing more significant snow. Clippers allow colder air from Canada to move into the area in their wake.