The Central Valley’s annual winter fog is especially thick this year, posing major hazards to road travelers and causing Clovis Union Station’s first foggy bus schedule in more than two decades.
What causes the persistent smog?
Brian Oaks, a meteorologist with the National Weather Service’s Hanford office, said the foggy conditions lasted longer throughout the day because of extra moisture left behind by previous storm systems.
Oaks said an inversion layer above the valley keeps the weather stable, allowing foggy conditions to rage without wind or rain to disrupt it.
Oakes said that while temperatures typically decrease with altitude, an inversion layer will cause temperatures to increase until about 4,000 feet. This stable, high-pressure system both absorbs moisture and protects against weather disturbances.
The fog is expected to persist in the valley until at least the weekend.
Driving on the roads is particularly dangerous due to the smog. One person was killed in a 17-vehicle pileup on Highway 99 in Fresno over the weekend. This week, a pedestrian was involved in a hit-and-run crash in thick fog, and a pickup truck driver was killed when he collided with a big rig.
