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
CLIPPERS.

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
ACCUMULATION.