A Blizzard Warning represents the highest level of threat for severe winter weather, signifying that life-threatening conditions are expected or already occurring. This official alert is issued by the National Weather Service (NWS) across the United States to communicate the most dangerous winter storm events. Receiving this warning means that a combination of extreme factors is converging to create a perilous environment. It is an urgent call for communities to take immediate, protective action.
Meteorological Criteria
A Blizzard Warning is only issued when specific, simultaneous weather criteria are met for a sustained period. The storm must produce sustained winds or frequent gusts of 35 miles per hour or greater. This wind speed is powerful enough to create hazardous conditions regardless of the amount of new snow falling.
Coupled with these high winds, the warning requires considerable falling or blowing snow that frequently reduces visibility to one-quarter of a mile or less. This extreme lack of visibility is often referred to as a whiteout, which makes travel nearly impossible. These severe conditions must be expected to prevail for a minimum duration of three hours. The criteria define a true blizzard, differentiating it from a simple heavy snowstorm. The conditions can be met by heavy falling snow or by intense winds picking up snow already on the ground, which is known as a ground blizzard.
Alert Hierarchy and Severity Levels
The National Weather Service uses a tiered system to communicate the severity and certainty of winter weather events, with the Blizzard Warning representing the most severe end of the scale. A Winter Weather Advisory is issued for conditions that may cause significant inconvenience but are not expected to be life-threatening. This advisory level typically involves lesser amounts of snow, sleet, or ice accumulation.
A Winter Storm Watch is a less immediate alert, informing the public that conditions are favorable for a significant winter storm to develop within the next 12 to 48 hours. The Watch signifies a possibility for hazardous conditions, prompting people to prepare. A Warning means the dangerous event is either imminent or already underway and poses a direct threat to life and property. The hierarchy is summarized by the required action: a Watch means “Be Prepared,” an Advisory means “Be Aware,” and a Warning means “Take Action.”
Immediate Public Action
Upon the issuance of a Blizzard Warning, all unnecessary travel must be avoided immediately due to the high risk of whiteout conditions and becoming stranded. The combination of near-zero visibility and high winds makes driving exceedingly dangerous. If travel is unavoidable, a fully stocked winter survival kit should be in the vehicle, including blankets, flashlights, and a battery-powered radio.
The focus should shift to sheltering in place and ensuring the home is ready for a potential extended power outage. An emergency kit with at least three days’ worth of food, water, and warm blankets is necessary for every household member. Property owners should ensure all pets and livestock are brought into a sheltered area and that outdoor items are secured against the strong winds. Check that heating sources are functioning safely and that carbon monoxide detectors are operational, especially if alternative heating methods are used during a power loss.