The Brief Heavy fog and mist prompted a temporary ground stop for departing flights at Seattle-Tacoma International Airport on Friday morning. Air traffic alerts indicated the ground stop was scheduled until 9:30 a.m., with passengers advised to check directly with airlines for updates. Heavy fog and low visibility prompted aviation officials to issue a ground stop at Seattle-Tacoma International Airport on Friday morning, temporarily halting departing flights. (FAA)Sea-Tac Airport ground stop, delaysThe Federal Aviation Administration placed the restriction on departures as low visibility conditions enveloped the airfield. According to air traffic alerts, the ground stop is scheduled to remain in effect until 9:30 a.m. local time.