I was in the San Francisco Bay Area on July 4th, 1976. To celebrate the 200th Independence Day, the City of San Francisco set up an elaborate fireworks display on Alcatraz Island in the middle of San Francisco Bay, which made it visible from all over the area. That afternoon a group of friends and I went up to the Berkeley Hills, where we had unimpeded view of the Bay, Alcatraz, San Francisco, the Golden Gate Bridge, everything. We had a picnic with the usual stuff graduate students eat and then waited for darkness and the fireworks. Just as the sun was setting behind the Golden Gate bridge, the fog started rolling in from the ocean, blanketing first the Golden Gate, then all of San Francisco, then Alcatraz and finally reaching the Berkeley shore. At the appointed time, they set off the fireworks anyway. All you could see was flashes of light inside the fog.

One would have thought they learned a lesson that day ....