I received quite a few interesting emails, photos and even a couple of Facebook postings regarding last week's Weather Watch column “Mirages may play tricks on even seasoned sailors.”
As you may remember, mirages are caused when light rays are bent or refracted when they travel through mediums with different densities. For example, a pencil in a half-filled glass jar of water appears to be bent. Changes in air densities can produce some fascinating optical illusions in the atmosphere.
Thousands of years ago, the Chumash people named an island after a mirage. Tom Reilly from San Luis Obispo wrote on Facebook that Anacapa Island off the Ventura County coastline in the Southern California Bight got its name from a superior mirage.
He’s right; Anacapa comes from the Chumash word eneepah or 'Anyapakh, meaning Mirage Island. I was stationed at Naval Base Ventura County at Point Mugu. If the atmospheric conditions were just right, Anacapa would tower in the distance as seen from the concrete runways at the naval base.
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Mark Machala has worked at PG&E’s Diablo Canyon Power Plant for years. He, as well as hundreds of other employees who drive or ride in carpools along the scenic 7-mile access road that follows the rugged Pecho Coast to and from the nuclear power plant occasionally sees good examples of these optical phenomena. On rare warm and clear afternoons along the access road, Point Sal can loom large on the horizon through your windshield as you head home.
Suffice to say, if you happened to be on the other side of San Luis Obispo Bay, the Pecho Coast can also look bigger than life. Central Coast photographer Cathy Gregg, whose weather photos can often be seen on the National Weather Service Los Angeles/Oxnard website, took a fascinating Fata Morgana superior mirage image of Diablo Canyon back in January 2009 from Rancho Guadalupe Dunes Beach.
She said, “I noticed it because you cannot see Diablo Canyon from the beach there on a normal day.”
A Fata Morgana mirage distorts vertically as well as elongates far away objects. In Cathy’s photo, one of Diablo Canyon’s massive steel and concrete containment structures is plainly visible along with the brown turbine building. Both Diablo Rock and Lions Rock near the power plant seem to have twins, and the hillside near Point Buchon looks like some gigantic cantilevered cliff.
Mary Hanse read a book about her ancestor's passage to America from Portsmouth, England to New York in 1831. One paragraph in the book read, ‘The apparition of a ship bearing down upon us nearly before the wind in full sail, and so close that to avoid contact seemed almost impossible,’ " she said.
It seems that it was a mirage, in their opinion caused by the vapor of the cold weather and the warm Gulf Stream.