How does next week's giant swell stack up to the great ones of the past?

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SURF NEWS How does next week's giant swell stack up to the great ones of the past?

December 5, 2009

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Please download and install the latest version of Flash Player before continuing. HOW BIG IS BIG? How does next week's giant swell stack up to the great ones of the past? Well, the word is out. Surfers these days are so Internet savvy and in tune with the swell models like Surfline's LOLA that we often receive special forecasting requests days before the storm even happens. In this case, the Big Storm of 2009 will take place over the weekend of December 5th and it will spread so much purple in the LOLA models throughout the North Pacific that it will be impossible to miss the fact that we are on the verge of something very special. As Laird Hamilton famously stated a few years ago, "Purple is good" -- this is the color he looks for in the LOLA models to signify very large swells in excess of 30 feet. Of course rumors on the coconut grapevine have been in overdrive this past week with many claiming "Biggest Hawaii Swell Ever," "Bigger than the Makaha '69 Swell," "Bigger than the 1990 Eddie when Brock Little Paddled into a 30-foot Monster at Waimea." So when we decided to take a close look at this swell, we also thought it might be cool to do a little comparative research and compare it with a few of the great swells of the past. Whenever we have storms of this magnitude in the North Pacific with wind speeds over 50 knots, pressure in the 940mb range, and combined seas in excess of 45 feet, there is always one common contributing factor -- a large amount of tropical moisture merging into a cold storm to create an "extra-tropical" storm. The tropical moisture forces the air to rise violently in the storm to create lower core pressure, higher wind speeds and, therefore, larger seas and swell. In the satellite loop at left taken between November 25th and December 3rd, we see super typhoon Nida in the Western Pacific that was a Category 5 storm with wind speeds over 175 mph. As Nida begins to weaken, we see a large amount of tropical moisture being pulled up into the Northern Pacific that intensified our last few storms as well as the super-bomb scheduled for December 5th. This is like throwing 20 gallons of gas on an already raging bonfire on the beach. Watch out! El Nino conditions might also be a factor contributing to the storm's energy with slightly warmer ocean surface temperatures throughout the Central Pacific helping to keep a more southerly storm track along with lower storm core pressures and stronger winds and swell. But the real primary reason behind this great storm will be the tropical moisture fuel being added from Typhoon Nida. Our Big Storm of December 2009 will peak in intensity on Saturday, December 5th about 1500 miles north west of Hawaii with a 942mb central low pressure, top wind speeds of 55-65 knots, and combined seas of 45-50 feet. This storm track will travel from west to east above Hawaii - kind of crabbing sideways - so the swell actually could have been larger for Hawaii if the storm had tracked more from the northwest directly toward Hawaii. By late Saturday this will become a huge complex low pressure system with two circulating lows that will create a very long northwesterly fetch of nearly 2,000 miles of strong winds and swell toward Hawaii. Our Big Swell of December 2009 will peak on Hawaii's north shores on Monday and Tuesday, the 7th and 8th, with huge, 20-to 25-feet of deep-water swell. This will translate into surf with 20-to 40-foot faces in most northwest facing areas and larger sets approaching 50-to-60 feet on the face in select areas. But how does this compare to some of the biggest swells in history? The famous Eddie Waimea swell in 1990 had many similarities to our December 2009 swell (at least as it is modeled to happen this weekend). Both storms peaked in the same area about 1500 miles northwest of Hawaii in the 940mb range, there were 50-to 60-knot peak wind speeds, 45-to 50-foot-plus combined seas, and 20-to 25-foot deepwater swell on Hawaii's north shores. The 1990 storm may have tracked slightly better toward Hawaii than the 2009 storm -- as stated earlier, this one will be tracking a little more sideways from west to east. So I would estimate the 1990 and 2009 swells will be very, very similar and, if anything, I might give a slight nod to the 1990 swell for slightly better tracking toward Hawaii. The famous December 4th, 1969 swell was massive and most noteworthy for the infamous Greg Noll session at Makaha that history records as Noll's last big-wave session in Hawaii. Read more about that day here. http://www.legendarysurfers.com/surf/legends/lsc208.html#makaha_nov1969 There was a cool scientific study that provided a few charts of that storm. "Damaging Waves From A Distant Storm In 1969" (Reference: Matthews, L. S., 1971. Heavy swell observed in the South Pacific in December 1969. Technical Note 196 New Zealand Meteorological Service) MORE ONLINE