Drive Safely in Dense Fog

Posted on October 20, 2015

I recently got an email from State Farm Insurance titled “Drive Safely in Dense Fog”. Here’s a link to their tips. It reminded me of the scariest moment I had driving in fog, across the Richmond San Rafael Bridge over San Francisco Bay. It was so thick that the street lights on the bridge made it appear as if you were driving into a steel gray wall every 50 feet. Your main instinct is to slow down to a crawl, so you don’t collide with a stalled truck hiding behind that next image of a steel wall. At the same time, you know you can’t slow down too much or other drivers behind you, who have not slowed down, could run into your back end.


First a word about the fog in San Francisco. It’s thick, really thick and it gets concentrated into the funnel that is San Francisco Bay. The coast of California is usually cooled, even in the hottest summers, by the adjacent waters of the Pacific Ocean. Travel in from the coast 30 to 50 miles, over the low coastal mountain ranges and it’s a different story. August temperatures in the Sacramento Valley can be in the high ’90s even when it’s only 70 in San Francisco. As you know, heat rises, and the hot air in central California does just that. That rising hot air has to be replaced with air from somewhere and it comes from the Bay.


San Francisco Bay is shaped sort of like the number “8” with an extension in the middle to the left that is the Golden Gate. When the heat rises in the interior, the cool, misty ocean air collects along the coast, looking for a way to get in to cool things off. Some days the fog overspreads the city, but on other days, there is a definite delineation between the clear weather and the “pea soup”. Depending on conditions, one side of a street can be in bright sunshine while the other is gloomy.  Many days start off foggy until it burns off by Noon.  Generally speaking, the fog comes in through the Golden Gate and makes a left turn around Alcatraz before winding its way up through the north end of the Bay and eventually the Sacramento River heading northeast.

sf bay map

It was late evening when I took my scary ride across the bridge. It was so long ago that I’ve forgotten why I went (probably to see a girl). The stars were out in San Rafael and I could see the lights twinkling across the Bay. I guess I noticed the low clouds in the middle, but it didn’t make much of an impression, until I got to the middle of the span. The bridge is double deck style with the westbound traffic on top and the eastbound downstairs and no place to pull over to the side. The mercury vapor lights suspended from the upper deck glaring against the gray fog gave the appearance of driving in a steel walled room. Every 50 feet was a new room and I was certain I was going to smash into one of those walls.

The San Rafael Richmond Bridge is a complicated cantilever style bridge which has two high points, one for each lane of shipping traffic. Ocean going freighters ply the waterway to the Chevron refinery in Richmond as well as other heavy industry in the area. It is 5.5 miles long and provides clearance above the water of 185 feet. It is not as scenic or as heavily used as other bridges across the bay. That night, I felt like I was all alone on that massive structure.

Each “steel room” I went through made me more nervous than the last. I must have gone through 30 or 40 of them before emerging from the fog on the approach to the East Bay.  I was so unnerved by the experience that on my return trip, I drove south to the Bay Bridge, crossing into San Francisco and then up across the Golden Gate Bridge and back to San Rafael. That trip took about an hour longer but was a lot less frightening.

I’ve since moved to Chicago. We get fog every once in a while, but it’s not nearly as thick as it is on the coast and it’s more of a novelty. I’m sure the good people at State Farm insurance have some great advice on how to deal with fog, but I don’t think any advice could have helped me cope with the fog on the bridge over the San Francisco Bay those many years ago.