While 2004 saw no dearth of memorable events - the presidential election, a devastating tsunami and, to a lesser extent, Janet Jackson's Super Bowl halftime "display" - the year can also be noted for the weather the Southland experienced.
On paper, 2004's weather looks almost like any other year: The temperature remained near average, the Santa Ana winds arrived and the storm currently moving over Southern California put annual rainfall above average.
"When you look at the big picture, it all looks pretty normal. But when you look at the details, it was anything but normal," said William Patzert, a climatologist and oceanographer who researches weather for Jet Propulsion Laboratory. "It's kind of schizophrenic here."
Fall winds in December, winter rains in fall, spring temperatures in summer - 2004 was a hodgepodge of weather events brought on by the absence of an El Niño condition. This absence allowed for fluctuations in the Jet Stream, the fast-moving band of air that circles the Earth in the lower atmosphere, which sent storms from the North Pacific Ocean to the West Coast.
The rainfall total for the year appeared as if it would fall below the average of about 15 inches, as recorded at the Los Angeles Civic Center. But the storm that hit Monday has put the 2004 average above normal, with at least 6 inches falling from the sky. December had been relatively dry until Monday, with only six-tenths of an inch of rain having fallen, Patzert said.
The deluge flooded streets, caused power outages and raised the water level in Devil's Gate Dam to levels not likely seen since the last El Niño event in 1998. The county Public Works Department, which operates the dam, has been keeping water in it this year for systems tests. The 5.55-inches of rain that fell on Dec. 28 reportedly broke the record for rainfall on that day.
If this year-end storm had not occurred, rainfall would have been at 75 percent of normal, which has been the average in the last six consecutive years, Patzert said.
The year began with unusually cool January weather followed by a wet February, during which 4.88 inches of rain - nearly a third of the annual average - was recorded at the Los Angeles Civic Center, Patzert said.
Spring was predominantly warm and dry. From April to October there were 182 days without a drop of rain, Patzert said. Then the rains hit.
"All of a sudden October showed up and this is when the Jet Stream started doing strange things," Patzert said, alluding to the storms that were blown south from the frigid North Pacific.
In August, weather buoys off the coast of New Guinea began recording an increase in surface water temperatures in the equatorial Pacific Ocean, which National Weather Service researchers considered a precursor to an El Niño condition that could have sent storms north to California. But that did not occur, and within months the Jet Stream began experiencing fluctuations that carried slow-moving storms to the West Coast, a common occurrence when El Niño is a no-show.
In the midst of a six-year drought, October 2004 was the wettest October on record since 1889. That month's average temperature was 4.5 degrees cooler than normal and 4.56 inches of rain fell at the Civic Center, Patzert said.
At the heels of October's downpours came cold November weather that dropped just two-tenths of an inch of rain, about 20 percent of normal, the scientist said. Rains in late October caused a flash flood in a Little Tujunga Canyon creek that claimed the life of a night watchman at the Wildlife Waystation in Tujunga.
This would have been one of the driest years on record if February and October's rains had not occurred, Patzert said. With those months taken out of the rain record, about two-and-a-half inches of rain fell all year, he said.
The year's weather was not without its bright spots, Patzert said.
Cool summer weather improved air quality through its effect on the inversion layer, an area of cool air trapped below warmer air that typically creates poor air quality. And October's rains dampened what officials feared could have been a horrendous fire season.