Fog caused the cancellation of seven flights destined for the Medford airport Sunday evening and diverted several more Monday.
Airport Director Bern Case said an unmanned balloon system for dispersing dry ice pellets was able to break up the fog Monday morning, allowing for planes to come and go.
But once the temperatures rose above freezing, the dry ice pellets were no longer effective and several flights were cancelled or diverted.
"I know we missed a few flights," Case said. "It's been a tough fog day."
Case said Monday evening that the temperature had once again dropped to a point that his crews would be able to start using the dry ice pellets.
The fog is expected to remain in the area through today, and weather forecasters say it likely will have left an icy deposit overnight, making roads and walkways slippery. The National Weather Service on Monday put out a weather advisory, warning of freezing fog through noon today.
The fog should depart Wednesday as a wet system moves in, bringing rain to the Medford area and snow showers in higher elevations.
On Monday, departing passengers in Medford found there were no planes on the tarmac, meaning all commercial airlines were waiting for inbound flights to arrive from other West Coast airports.
"The one that came in, taxied back out and took off, probably for Portland but it could've been Seattle," Case said Monday morning. "It's been a little chaotic."
Case said passengers should stay in close contact with airlines.
"Don't assume they will be early or late," he said.
Visibility was well above the minimums this morning, Case said. But most of the 17 scheduled departures were in doubt because of Sunday's events.
"It's a double-whammy when planes can't get in," Case said. "Because you can't get out if you don't get in."
Thanks to the Cable Attached System Providing Effective Release — a helium balloon hoisting a 75-pound dispersal cylinder high enough to release fog-busting pellets — the airport was able to navigate through most of the wintry challenges posed last week.
"We had some delays and one diversion for an hour before it got back in the air and then here," Case said Monday morning. "As fog goes, last week went pretty well. Last night (Sunday), not so well."
"We got one flight in and the fog was so thick they gave up and had to be diverted," Case said.