A Heavy snow warning was a weather warning issued by the National Weather Service of the United States during times when a high rate of snowfall was occurring or was forecast. Generally, the warning was issued for snowfall rates of 4 inches (10 cm) or more in 12 hours, or 6 inches (15 cm) or more in 24 hours.
This warning was discontinued beginning with the 2008-09 winter storm season, replaced by the Winter Storm Warning for Heavy Snow.
A similar warning is issued by Environment Canada's Meteorological Service of Canada
Example of a heavy snow warning
URGENT - WINTER WEATHER MESSAGE NATIONAL WEATHER SERVICE FAIRBANKS AK 221 PM AST SUN DEC 9 2007 .A STORM SYSTEM MOVING NORTH OVER THE CENTRAL BERING SEA WILL MOVE TO SOUTHWEST OF SAINT LAWRENCE ISLAND MONDAY AFTERNOON. THE STORM WILL BRING SNOW AND EAST WINDS OF 30 TO 45 MPH TONIGHT OVER MUCH OF WESTERN ALASKA FROM THE YUKON DELTA TO THE SEWARD PENINSULA TONIGHT. WINDS WILL DIMINISH EARLY MONDAY BUT SNOW IS EXPECTED TO CONTINUE THROUGH MONDAY AFTERNOON. AKZ212-100600- /X.CON.PAFG.HS.W.0011.071210T0000Z-071211T0200Z/ EASTERN NORTON SOUND AND NULATO HILLS- INCLUDING...UNALAKLEET...STEBBINS...ST MICHAEL...ELIM...KOYUK... SHAKTOOLIK 221 PM AST SUN DEC 9 2007 ...HEAVY SNOW WARNING REMAINS IN EFFECT UNTIL 5 PM AST MONDAY... A HEAVY SNOW WARNING REMAINS IN EFFECT UNTIL 5 PM AST MONDAY. SNOW WILL SPREAD INTO THE AREA SOUTH OF UNALAKLEET THIS AFTERNOON...AND WILL SPREAD NORTH TONIGHT...AND CONTINUE INTO MONDAY. SNOWFALL ACCUMULATION OF 6 TO 10 INCHES ARE EXPECTED WITH HIGHEST AMOUNTS ACROSS THE NULATO HILLS. EAST WINDS WILL INCREASE TONIGHT TO 25 TO 35 MPH AND SOME VISIBILITIES WILL BE REDUCED TO ONE-QUARTER MILE AT TIMES IN BLOWING SNOW. A HEAVY SNOW WARNING MEANS HAZARDOUS WINTER WEATHER IS EXPECTED. THE ACCUMULATION OF NEW SNOW WILL MAKE TRAVEL DIFFICULT. $$References
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