Critical conditions

The weather year started out with plenty of rain to keep the North Coast green and fill lakes and reservoirs.

By the end of January, Santa Rosa's rainfall was three inches above normal. Coming off a weather year in which it had been down 30 percent, the forecast was positive.

But in late February, something went terribly amiss, resulting in the driest spring on record in Sonoma County and throughout much of California.

The jet stream, the storm superhighway that flows through Northern California each winter, moved farther north into northern Washington and British Columbia, and the rain spigot shut off.

"It definitely left us high and dry," said Mike Anderson, the climatologist for the state Department of Water Resources. "This year the whole Pacific Coast was getting precipitation. We were close to average at the end of February, but then nothing happened in March, April and May. It was not the spring like we would have expected."

As a result, the parched Northern California landscape is ripe for the wildfires now raging.

"We are at pretty critical conditions right now," said Dave Shew, a battalion chief for Cal Fire on the Walker fire in Lake County. "The fuel moisture is at its lowest point for this time of year we have ever seen. What that means is the vegetation and fuel is more readily ignited."

The lack of rain has left Lake Mendocino with too little water for the fall salmon run, prompting the Sonoma County Water Agency for a second consecutive year to ask for conservation measures.

"People talk about climate change. . . . It makes you scratch your head," said Don Seymour, a principal engineer at the Sonoma County Water Agency.

The weather year, which runs from July 1 to June 30, ends today.

Statistically, Santa Rosa has received 24.03 inches of rain. That is less than the 31.01 inches that has been the average for the past 30 years, but more than the 20.45 inches that fell in the 2006-2007 weather year.

The rain, however, came early. There was above-average precipitation in October, December and January. At the end of January, Santa Rosa had 20.54 inches of rain, above a normal 17.54 inches for that time of year.

The weather year can be explained by La Niña, a cold band of water extending from the west coast of South America to the international dateline that is a harbinger of a wet year for the Pacific Northwest.

"We had strong storm events in January and through late February. Then nothing happened; there was less than an inch of rain after March 1," Seymour said.

That's because in late February, La Niña left and the weather changed dramatically.

Later in the weird weather year, a northwest flow of cold air from Alaska brought freezing temperatures to vineyards in Sonoma and Mendocino counties. Some grape growers ran frost protection 30 times in April and May, six times what they would do in a normal spring.

In the months of March, April, May and June, Santa Rosa gets on average 7.4 inches of rain. This year, .65 of an inch fell, the lowest rainfall on record for those four months.

"This was the driest spring on record for many areas," Anderson said. "For Sacramento, for many of our departments, for our eight-station rain index, it was the driest on record as a whole."

Because of the dry spring, the amount of water in Lake Mendocino is 66,500 acre-feet, below the 85,000 acre-feet the Water Agency wants this time of year to ensure enough water for the release in October for the spawning run of chinook salmon, which are on the federal endangered list.

It has prompted the Water Agency to ask for a 15 percent cut in water usage, with the water withheld in Lake Mendocino.

That is the same amount of conservation that was requested last year of the agency's major buyers, which are the cities and water districts from Windsor to Sausalito, serving 600,000 residents.

It could have been worse, but the Water Agency took over control of the releases from the U.S. Army Corps of Engineers at Lake Mendocino on March 1, a month early, and held back water in the flood control pool in anticipation of the dry spring, Seymour said.

The water held back could be as much as 9,000 acre-feet.

Cal Fire also anticipated problems in the dry year, hiring an additional firefighter for each engine and manning stations and the air attack bases earlier.

"We hired people earlier. We hired more than we would, but we are still faced with a pretty significant series of fire events in the state," Shew said.

You can reach Staff Writer Bob Norberg at 521-5206 or bob.norberg@pressdemocrat.com