Winter storm warning
A Winter Storm Warning means a significant winter event with snow, ice, sleet, or blowing snow is happening or about to happen, and the local National Weather Service forecast office issues it. It usually comes closer to the event than a watch, which typically goes out within 48 hours. The exact thresholds vary by office; for the Baltimore/Washington area, the warning goes out for 5 or more inches of snow or sleet, ice capable of causing damage, or a combination of wind and other hazards that can put lives at risk.
Right now0Winter storm warnings in effectas of Snow totals by state, measured
Watch vs warning vs advisory
| Term | What it means | Typical lead time | Typical amount (Baltimore/Washington) | What to do |
|---|---|---|---|---|
| Watch | Conditions are favorable for a significant winter storm, such as heavy snow, heavy sleet, an ice storm, or snow with blowing snow. | Usually within 48 hours | No fixed amount; the storm could reach warning levels. | Be prepared. Monitor forecasts and make a plan. |
| Warning | A significant winter event with snow, ice, sleet, or blowing snow is happening or about to happen. | The watch usually gives way to the warning 12 to 36 hours before the event. | 5 or more inches of snow or sleet in most of the area, 6 inches in the six westernmost counties, ice capable of causing damage, or a combination of wind and other hazards that can put lives at risk. | Take action. Stay off roads if possible and follow safety steps. |
| Advisory | Wintry elements are expected but below warning criteria. | Varies; issued when conditions are expected. | 2 to 4 inches of snow or sleet (3 to 5 inches in the west), 1 inch in the metro during rush hour, or any freezing rain. | Be aware. Use caution, especially on roads. |
What counts as significant
- Snow, sleet, ice, or blowing snow that reaches the local office's warning threshold.
- Blizzard Warning, which adds winds of 35 mph or more and visibility under 1/4 mile for at least 3 hours.
- Ice Storm Warning, for about 1/4 inch of ice accumulation or more.
- Lake Effect Snow Warning, used by some Eastern Region offices for heavy snow from lake-effect bands.
Safety steps while a winter storm warning is active
- Stay off roads during the worst of the storm.
- Stock up on food, water, and medicine for 2 to 3 days.
- Keep a winter car kit in case you must travel.
- Heat your home safely; never run a generator indoors.
- After the storm, check measured snowfall totals.
How the warning reaches you
Most areas do not send a Wireless Emergency Alert for a standard Winter Storm Warning; those alerts go out for Blizzard Warnings, Ice Storm Warnings, and significant snow squall warnings. The National Weather Service still distributes Winter Storm Warnings through weather.gov, NOAA Weather Radio, and local TV and radio. Since 2017, the warning text has followed a What, Where, When, Additional details, and Precautionary actions format.
How much actually fell
After the storm passes, this site posts measured totals for cities and states. Check the snow totals by state page for the official numbers from each event.