A ground stop is an order from the Federal Aviation Administration (FAA) that keeps flights bound for a specific airport on the ground at their departure airports. It's the strongest everyday tool air traffic control has to protect an airport that can't safely accept the number of arrivals headed its way.
Why ground stops happen
An airport can only land so many planes an hour. When that rate suddenly drops, a ground stop stops more flights from piling up. Common causes:
- Thunderstorms over or near the airport or its arrival routes, the most common cause in summer.
- Low ceilings and visibility (fog, low clouds), which force wider spacing between arrivals.
- Wind that forces a switch to fewer or less efficient runways.
- Volume: more scheduled flights than the airport can handle at that moment.
- Equipment or staffing problems, such as radar, radio or computer outages, or a short-staffed control facility.
- Runway closures, disabled aircraft, security events, or other emergencies.
Separately, airlines sometimes ask for a ground stop of their own flights after an IT outage. Those are company-specific and usually aren't listed as airport ground stops.
What happens to flights
- Flights to the affected airport from the airports included in the ground stop stay at the gate (or are held before takeoff).
- Flights already in the air keep flying, though they may be slowed down or put in holding.
- Flights to every other destination are unaffected.
A ground stop names the departure scope: which air traffic control centers' airports are included. Nearby centers are almost always included; a severe event may include every center in the country ("ALL"), and sometimes Canadian airports too. That's why a storm in Dallas can keep you at the gate in Chicago. See what an ARTCC is.
How long it lasts
Most ground stops are short, often under an hour or two. Each one is issued with a scheduled end time, and the FAA publishes a probability of extension (low, medium or high). If the problem continues, the stop is extended or replaced with a ground delay program, which lets flights depart at assigned times instead. See how long ground stops last for real numbers.
How to check for a ground stop
The FAA publishes ground stops on its National Airspace System status page. GroundStop.app reads those feeds every minute and shows them on a live map, with each ground stop's reason, end time and the centers whose departures are held. Every major airport has its own page, for example Newark, Chicago O'Hare and San Francisco. For your specific flight, always check with your airline.