COUNTYWIDE : Dense Morning Fog Covers Inland Areas

Thick fog Monday morning cut visibility to zero in some places in Orange County, but the California Highway Patrol and authorities at John Wayne and Fullerton airports reported no major problems.

The fog, which burned off by 9 a.m., was caused by a high-pressure system descending on the marine layer and forcing the condensed air to ground level, according Marty McKewon, a meteorologist with WeatherData Inc., which provides forecasts for The Times.

Dense patches of fog rolled into coastal and inland cities early in the morning, catching many inlanders by surprise.

Lisa Arnold, an air traffic controller at Fullerton Municipal Airport, reported that there was zero visibility when the facility opened shortly before 7 a.m. “The fog was just sitting on the ground, and the sky was totally obscured,” she said.

Rush-hour traffic was significantly slowed as the fog shrouded freeways and surface streets throughout the county. Kathleen Smith of Anaheim said she could barely see through her windshield when she drove to classes at Fullerton Junior College.

“It’s not normal for us to get such thick fog so far from the beach,” Smith said. “Everyone was straining to see in front of them.”

The early-morning fog should continue through at least today, McKewon said, and likely will move farther inland later in the week.

The CHP advises motorists driving in foggy areas to reduce speeds and use headlights on low beam.