Winter weather alerts communicate urgency, but the terminology confuses many people. Understanding the difference between a watch, advisory, and warning can guide your preparation and response.
Alert Hierarchy
The National Weather Service (NWS) and Environment Canada issue tiered alerts. Severity increases from advisory to warning. Watches indicate conditions may develop; warnings mean conditions are occurring or imminent.
Common US Winter Alert Types
Winter Storm Warning
Issued when significant snow, ice, or sleet is expected. Criteria vary by region but typically involve 6+ inches of snow or significant ice accumulation within 12 hours. Take protective action immediately.
Winter Weather Advisory
Less severe than a warning but still impactful. Expect travel difficulties. Often issued for 3 - 5 inches of snow or light ice accumulation.
Blizzard Warning
Sustained winds of 35 mph or greater with considerable falling or blowing snow reducing visibility to less than a quarter mile for three or more hours. Travel becomes life-threatening.
Ice Storm Warning
Significant ice accumulation (typically ΒΌ inch or more) expected on exposed surfaces. Power outages and tree damage are likely.
Wind Chill Warning / Advisory
Dangerously low wind chill values. Frostbite can occur on exposed skin within minutes during warnings.
Freeze Warning
Below-freezing temperatures expected during growing season - less common in mid-winter but relevant for southern regions.
How to Respond
- Warning - Stay off roads. Complete storm preparations immediately.
- Advisory - Limit travel. Allow extra time. Monitor updates.
- Watch - Review plans. Ensure supplies are stocked. Stay informed.
Alerts and School Decisions
Superintendents monitor NWS alerts closely. A Winter Storm Warning issued the evening before often precedes closure decisions. Use our Winter Storm Risk Calculator alongside official alerts for local context.
Canadian Alerts
Environment Canada uses similar terminology with regional variations. Winter storm, blizzard, and extreme cold warnings serve equivalent functions. Check weather.gc.ca for official Canadian alerts.