Ice closes schools at totals that look embarrassing on a snow stake. A quarter inch of freezing rain can beat 6 inches of dry powder because buses cannot climb glazed hills and cannot stop on untreated side streets. If your forecast says “snow, maybe a little ice,” treat the ice as the headline.
Not an official closure notice. Confirm with your district.
Why ice wins
- Tires need friction. Glaze removes it. Plow blades scrape snow. They do not magically de-ice a hill in 20 minutes.
- Freezing rain on trees takes down power. A building without heat or lights is a facilities close, not a snow close.
- Refreeze after a thaw (afternoon melt, overnight flash freeze) creates black ice at 5 AM even if yesterday’s snow looked friendly.
Planning ranges (not laws)
| Condition | Typical K-12 reaction |
|---|---|
| Dry powder, plow-rich city | Often delay, sometimes open |
| Wet snow near 32 F | Closes faster than the inch number suggests |
| Freezing rain or sleet | High closure risk even under 1 inch liquid equivalent |
| Thunderstorms with ice (southern events) | Often a full day or more; equipment is scarce |
Southern and mid-Atlantic districts close on ice more than on snow. Buffalo will drive through powder that would shut Atlanta. That is infrastructure, not toughness.
How our calculator treats ice
We pull ECMWF and NOAA hourly fields and weight ice risk inside the 4 to 7 AM window. A low snowfall total with freezing precipitation should not look “safe” in the score. If it does for your ZIP, still defer to the district. Models underdo freezing rain more often than they underdo powder.
Check your ZIP · Delay vs snow day · Wind chill closures
Frequently asked questions
Can school close with no snow on the grass?
Yes. Ice, wind chill, flooding, and facility failures all cancel class with a green lawn.
Is sleet as bad as freezing rain?
Sleet is pellets. It can pack and get slippery, but freezing rain that coats pavement is usually the worse bus problem.