Public Information Statement
Issued by NWS State College, PA
NOUS41 KCTP 081056
Public Information Statement
National Weather Service State College PA
556 AM EST Tue Nov 8 2016
The week of November 7th to 11th is Winter Weather Awareness Week
Each day we will feature a different educational message concerning
the dangers and safety concerns associated with winter weather.
TYPES OF HEAVY SNOW EVENTS WHICH IMPACT PENNSYLVANIA.
Heavy snow can immobilize a region and paralyze a city, stranding
commuters, closing airports, stopping the flow of supplies, and
disrupting emergency and medical services. Accumulations of snow can
cause roofs to collapse and knock down trees and power lines. Homes
and farms may be isolated for days and unprotected livestock may be
lost. The cost of snow removal, repairing damages, and the loss of
business can have severe economic impacts on cities and towns.
Heavy snow can be produced by noreasters, blizzards and overrunning
situations. Lesser amounts of snow are often produced by Alberta
Noreasters are intense areas of low pressure that typically
develop along the eastern seaboard most often during late fall,
winter and early spring. They usually bring strong northeast winds
to areas near the coast as they move north along it. Some memorable
noreasters in recent years included the Presidents Day snowstorm
of 2003, the February 11th and 12th storm of 2006, the Valentines
Day snowstorm of 2007 and the snowstorm of February 25th and 26th,
2010. Snowfall rates in noreasters can reach 2 to 4 inches per hour
and these rates can last for several hours.
Overrunning can also produce heavy snow. This occurs when warm
air aloft flows over cold air near the surface. Overrunning happens
mostly during the winter when the contrast in airmasses is greatest.
Overrunning occurs most often when a large dome of high pressure is
located in southeastern Canada and a warm front is approaching our
region from the south or southwest.
An Alberta clipper is an area of low pressure that usually
develops over the province of Alberta in Canada, east of the Rocky
Mountains. Alberta clippers usually move very quickly southeast from
their point of origin and usually bring only light snow as they
cross our region unless they intensify off the east coast. They also
allow colder air from Canada to move into our region in their wake.
Some snow terms which are commonly used include blizzard, blowing
snow, snow squalls, snow showers and snow flurries.
A blizzard is a winter storm which has sustained winds or
frequent gusts of 35 mph or more, with considerable falling and or
blowing snow frequently reducing the visibility to at or below one
quarter mile, and these conditions last for 3 hours or more. Some of
the greatest snowfalls on record in Pennsylvania occurred during
blizzards. 1 to 2 feet of snow fell over a large part of
Pennsylvania during the blizzard of 1993.
Blowing snow is wind driven snow that reduces visibility.
Blowing snow may be falling snow or snow already on the ground that
is picked up by the wind.
Snow squalls are brief intense snow showers accompanied by
strong gusty winds which may produce significant snow accumulations.
Snow showers have snow falling at varying intensities for brief
periods of time with some snow accumulation possible.
Snow flurries are light snow which falls with little or no snow