What is a snow squall?
A burst of heavy snow and wind that turns a clear road into a whiteout in minutes, then moves on. Little snow, a lot of danger.
By Petar M., editor · Updated October 18, 2026 · How we research
In this guide (5)
What a snow squall is
A snow squall is a short, intense burst of heavy snow with strong gusty winds. The National Weather Service describes squalls as very short-lived, on the order of 30 to 60 minutes, and extremely intense. They usually leave an inch of snow or less.
The danger isn't the amount. It's how fast conditions change:
- Sudden whiteout. Visibility can drop from miles to almost nothing in seconds, often on a road that was dry.
- Flash freeze. Temperatures fall as the squall passes, so wet roads can ice over within a few minutes.
- Chain-reaction crashes. Drivers at highway speed suddenly can't see, which is why squalls cause pile-ups.
What a Snow Squall Warning means
A Snow Squall Warning means a squall is happening or about to, for a specific area drawn on a map (a polygon), not a whole county. The NWS issues one when snow cuts visibility to a quarter mile or less on below-freezing roads, or when temperatures are dropping fast enough for a flash freeze. A warning is usually valid for only 30 to 60 minutes. All NWS forecast offices began issuing them in November 2018.
The NWS advice: if a Snow Squall Warning is issued for your area, avoid or delay travel until the squall passes. If you're already driving and can't get off the road in time, slow down, turn on your headlights and hazard lights, leave plenty of distance to the car ahead, and don't slam on the brakes.
Will my phone get an alert?
Only for the most dangerous ones. Since the 2022–23 winter, a Snow Squall Warning sends a Wireless Emergency Alert to phones only when the forecaster tags it as significant. Every Snow Squall Warning still goes out on NOAA Weather Radio and the Emergency Alert System, and to weather apps.
Snow squall vs. blizzard
| Snow squall | Blizzard | |
|---|---|---|
| How long | About 30–60 minutes | Three hours or more |
| Wind | Strong gusts, no fixed threshold | Sustained winds or frequent gusts of 35 mph or more |
| Visibility | A quarter mile or less, suddenly | Frequently under a quarter mile |
| Snow | Usually an inch or less | Falling or blowing snow, any amount |
| NWS alert | Snow Squall Warning | Blizzard Warning |
Can a snow squall close school?
Rarely by itself. Squalls are too short and leave too little snow for a district to close a whole day for one, and they are hard to predict hours ahead. They matter most when one hits at bus time: a squall at 7 AM can make districts delay buses or hold students, and one in the afternoon can slow dismissal.
The calculator gives a Snow Squall Warning a small boost to the chance of a closure, less than a Winter Weather Advisory, because it only matters if it lines up with the morning commute.How each NWS winter alert counts.
Check your district
See tomorrow's chance of a closure or delay for your ZIP code. Open the calculator, or find your state or city.
Sources
- National Weather Service, snow squalls (winter safety)
- NWS Service Change Notice 18-90: Snow Squall Warnings operational, Nov 2018
- NWS Instruction 10-513, winter weather products (criteria)
- NWS: Snow Squall Warnings with impact tags (2022)