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Cal Tech professor brings surf forecasts down to earth
by B. Baird
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Cal Tech professor Andy Ingersol helps local surfers get their arms around the wave forecast for Jupiter. The surfing professor spoke at the Ohana Nalu/Surf Academy Surf Expo Sunday at St. Cross Church. Photo by B. Baird |
Why are set waves bigger than other waves? Is the ninth wave of a set the biggest? Why are jet skis used instead of Zodiacs to tow surfers into big waves.
Local surfer Andy Ingersol had the answers at the Ohana Nalu/Surf Academy Surf Expo at St. Cross Church on Sunday. Over 100 people attended the expo, which also featured less scholarly topics such as board shaping and surf fashions. Surfers who attended were encouraged to donate old surfboards and wetsuits, which are to be donated to inner city kids.
Set waves are bigger than their accompanying waves, Ingersol explained, because they are formed by two waves from different sets merging together. And because of this, the biggest wave in a set is formed randomly. Which means, when a set approaches take the first big wave because it is just as likely to be the biggest wave in the set as the ninth or any other wave in the set.
The reason jet skis are preferred over Zodiacs by tow-ins surfers such as Laird Hamilton, is because big waves approach the outer reefs at speeds of up to 50 miles per hour. Zodiacs are too slow, Ingersol explained.
The speeds at which waves travel also explains why ground swells are rarely less than 13 seconds apart. The faster the wind that forms waves, the closer the intervals. Wind of 80 miles an hour produce waves that are roughly 13 seconds. And since winds rarely exceed 80 miles per hour, the intervals are rarely less than 13 seconds.
Ingersol was able to answer these questions because when he isn’t surfing, he’s studying the weather. His job, as a professor at California Institute of Technology, is to figure out why storms on earth last only a few days while storms on planets such as Jupiter last several centuries. Jupiter’s famous "red spot" is a 300 year-old storm, Ingersol said.
Though it is fortunate for the earth that storms rarely last as long as a week, there is a downside to this fact. Predicting the weather more than a week in advance is dicey. Ingersol told the story of a Cal Tech professor in the early 1940s who had a comfortable side business providing months-in-advance weather forecasts to movie studios. General Dwight Eisenhower reportedly called on the professor for advice in planning the Normandy invasion.
The professor was eventually dismissed for scientific fraud.
Scientists have had somewhat better success, Ingersol said, predicting long range weather conditions, such as El Ninos. El Ninos typically run in three to seven year cycles, according to records dating back to the ancient Egyptians. Since the last El Nino was in 1998, Ingersol said we are do for another on in the next few years. But with a scientist’s characteristic caution, he declined to say which of the next few years. ER