FOG CITY

Do you like secrets? Well, I do, and I want to share one with you: I love fog! Some people complain about the weather the fog brings, but not me. And I live in a very special place for fog magic - San Francisco. In the summer, it's especially welcome, acting like nature's air conditioner. It begins to flow through and under the Golden Gate Bridge in the afternoon and continues through the night, burning off by late morning. My favorite fog time is twilight, when it melts over the jagged cliffs and rolling hills of the bay like vanilla ice cream, cooling the summer day. Sometimes, I imagine the Golden Gate Bridge is a frothy banana split - complete with the setting sun for a cherry.

During the summer months, the fog in San Francisco Bay is formed in two ways: PUSH and PULL. The PUSH is from the warm Pacific air blowing off the ocean. When this warm air touches the colder water: presto! fog is created. It looks like a low flying cloud lying on the water (fog is a low flying cloud, formed of water droplets or ice crystals).

The second actor in this fog spectacular is the PULL. As heat from the inland valley rises, the Pacific air is sucked in to replace it - through the large mouth of the bay. This fog surges inland like towering ocean breakers, covering mountains and valleys in a sea of white vapor.

H-o-o-o-t! H-o-o-o-t! Do you hear that sound? No, it's not a train whistle; it's the foghorns. H-o-o-o-t! The fog is slowly rolling under the Golden Gate Bridge.

A few early morning fishing boats puttering to sea vanish - except for their blinking lights. Can you see them blinking?

I wonder how it feels to be on one of those boats, hidden beneath a cloudy cloak - misty and damp or soft as duck's down? And how does it smell - clean or fishy? Does fog have a taste - is it salty as sea foam or sweet like whipped cream?

It must be difficult to watch where the boats are going. See the silhouettes passing, almost invisible? What is it - a freighter headed for Japan? It's good that there are horns and lighthouses to guide them. Clang! Clang! Oh, yes - buoys too. I like the bright red and white buoys best, with big bells that clang. Some have flashing lights.

Often the fog will stop at the shore, making a giant, billowing curtain. You can stand right beside the ocean and not be able to see a drop. But you can hear it: Slap! Slap! the waves are pounding the beach. And do you hear the harbor seals and sea lions barking? I bet they like fog, too - it's gray and slippery, just like them.

Fog really is a friend to the growing things in our parks and forests. When a heavy bank of fog gets caught in the eucalyptus groves and Monterey pines, it leaves needed moisture. Drip! Plop! it even sounds like rain as it gathers on leaves and then falls. In Muir Woods, the ancient redwoods shimmer silvery green in its mystical vapors. These coastal fogs provide water for the giant trees during long, rainless summers.

There's fog magic in the city, too. I like how the sidewalks and cable car tracks smell - all wet and metallic. And have you noticed the way streetlights glow fluorescent in its mists? W-h-o-o-o-s-h! Hold on to your hats!

Some days, the fog breaks up its peaceful low-flow pattern. It races all around downtown in impudent puffs, playing hide-and-seek with the skyscrapers on Nob Hill and Russian Hill. If the fog is especially thick and wet, the traffic police and cable car drivers will put on yellow rain slickers. And, just when you think it might really rain or be cloudy all day - Poof! the fog disappears, and the sun is shining everywhere.