Ground stop at Seattle-Tacoma (SEA), Nov 12, 2026

EndedConstruction halts Seattle departures for 19 minutes

Started: Thu, Nov 12, 5:26 PM PST01:26 UTC
Ended: Thu, Nov 12, 5:45 PM PST01:45 UTC
Duration: 19 min
Cause: other

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What happened

AI-written · may contain mistakes. Written from the advisory text and weather only.

Cause: Construction work at Seattle-Tacoma and nearby Boeing Field led air traffic control to briefly stop flights from leaving Seattle. Weather was not the cause.

The ground stop began at 01:26 UTC on November 13 and was set to run until 02:00 UTC. Departures were held from three air traffic control centers, including Salt Lake City, Oakland and Seattle centers. It ended at 01:45 UTC, after 19 minutes, and was not extended. A ground delay program was expected to follow.

Impact by airline

Aircraft seen on the ground at SEA and holding nearby, by airline.

Airline	On ground	Holding
Alaska Airlines AS	9	—
Delta Air Lines DL	5	—
Horizon Air QX	2	—
American Airlines AA	1	—
Empire Airlines PN	1	—
Frontier Airlines F9	1	—
SkyWest Airlines OO	1	—
United Airlines UA	1	—

Impact by region

Air traffic control centers whose departures to the airport were held.

Center	Status
Salt Lake City Center (ZLC)	Held
Oakland Center (ZOA)	Held
Seattle Center (ZSE)	Held

Aircraft at the airport

Peak 19 on the ground, 0 holding nearby.

On the ground Holding nearby

Timeline

Every change published while the ground stop was in effect, as seen each minute.

Nov 12, 5:26 PM PST
Ground stop issued at SEA for other, until 6:00 pm PST. Departures held from ZLC, ZOA, ZSE.
Nov 12, 5:45 PM PST
Ground stop ended after 19 min.

Advisories

The air traffic control advisories issued for this ground stop, as published.

ATCSCC ADVZY 010 SEA/ZSE 11/13/2026 CDM GROUND STOP

CTL ELEMENT: SEA
ELEMENT TYPE: APT
ADL TIME: 0121Z
GROUND STOP PERIOD: 13/0106Z - 13/0200Z
DEP FACILITIES INCLUDED: (Manual) ZLC ZOA ZSE  CYEG CYVR CYYC CYYJ
 CYLW
PREVIOUS TOTAL, MAXIMUM, AVERAGE DELAYS: 0 / 0 / 0
NEW TOTAL, MAXIMUM, AVERAGE DELAYS: 213 / 37 / 18
PROBABILITY OF EXTENSION: MEDIUM
IMPACTING CONDITION: OTHER / OTHER
COMMENTS: CONSTRUCTION AT SEA AND BFI. GDP TO FOLLOW.

Original advisory ↗

How it is measured

Status, timeline, cause and held centers: the national airspace status feed, checked every minute, and the air traffic control advisories it links to.
Delays by airline and region: departures and arrivals at SEA 30 or more minutes late, by their estimated delay against the schedule, sampled every 10 minutes while the stop is active and once more after it ends.
Totals and cancellations: arrival and departure boards for SEA, every 30 minutes while active and once more after the end. Delayed means 15 or more minutes late at SEA; cancelled is the airline's cancelled status; codeshares count once. Flights scheduled from the start until an hour after the end are counted.
Held at origin: the same arrivals boards, which carry each flight's scheduled and actual departure from its origin. A flight is held when it is still scheduled, not departed, 15 or more minutes past its scheduled departure at a sample taken during the stop. In scope: its origin is in a held center or listed facility; flights from elsewhere are late for other reasons.
Inbound in the air: the same arrivals boards. At each board taken during the stop, a flight to SEA is in the air when it has departed (en route, or with an actual departure time) and not landed, cancelled or diverted; one still shown in the air over an hour past its arrival estimate, or departed more than 18 hours earlier, is treated as stale and left out.
Diversions: an inbound flight marked diverted during the stop or the wrap-up after it (not one marked before it could have departed), or one still shown in the air 30+ minutes past its arrival estimate that ADS-B (by its ICAO call sign) then found on the ground at another airport, not its origin. The diversion airport is the airport ADS-B found it at, else the updated destination. Cancellations never count. Regional flights flown under another call sign can't be found on ADS-B, so their diversion airport may be unknown.
Aircraft on the ground and holding: ADS-B positions around SEA, every 5 minutes; the airline is read from the call sign. Holding counts airline flights only (passenger, regional and cargo), not private, military or medical flights.
Weather: METARs, SIGMETs and weather alerts.
News: headline links filtered to this airport and these days; we show titles and links only.

Data sources are listed on the credits page.