A Winter Storm Warning is issued when dangerous winter weather is expected to threaten life or property. According to the National Weather Service, it signals a high likelihood of heavy snow, sleet, freezing rain, or a combination that can cause major disruptions. Typical criteria include six inches of snow in 12 hours or eight inches in 24 hours, though thresholds vary by region. Travel may become difficult or impossible, and residents are urged to delay plans and prepare for hazardous conditions.