OREGON STATE UNIVERSITY

Good news in the forecast? Oregon could face wet spring

02/09/2005

CORVALLIS - Oregon's dry winter is bad news for rain lovers, but if history holds true, Pacific Northwest residents may be in for a wet spring.

"Historically, dry winters preceded by a wet fall are very likely to be followed by a wet spring," said George Taylor, an atmospheric scientist at Oregon State University who serves as the state climatologist.

And late last summer, through early fall, it was wet.

Portland was 1.75 inches above normal for August precipitation, hitting 2.68 inches for the month. September actually dipped below normal by 0.62 for the Portland area, but the rain was back in October, hitting 0.48 inches above normal.

"There are always a lot of variables in rainfall for specific spots throughout the region," Taylor said, "but in general, August, September and October were wetter than average throughout Oregon."

Then came November and wet and wild turned into dry and mild, said Taylor, a faculty member in OSU's College of Oceanic and Atmospheric Sciences.

Precipitation totals at Taylor's home base in Corvallis show 12.08 inches of precipitation from October 2004 through January 2005. That's the seventh driest such period on record for the Corvallis area since records started being kept in 1889, he said. In a normal year, precipitation would total 23.85 inches during the four-month span.

Statewide, it was the same story, except in southeastern Oregon, which actually has done better than the rest of the state this winter, Taylor said.

"Ironically, southeast Oregon has been the driest part of the state for the last several years," he pointed out. And while the dry weather has made everyone from farmers to municipal water managers nervous, if history repeats itself, the state may escape water woes this summer.

"We don't even need a particularly wet spring," Taylor said. "For example, 15.58 inches is the normal rainfall for February through May in Corvallis. If we got 10 to 12 inches of rain or more for that period, it would probably be OK - it would help a great deal."

Even Oregon's dismal snowpack, which is at 32 percent of normal in early February, while disheartening, isn't necessarily ruinous.

"We still have time for it to build," Taylor said, explaining that snow typically accumulates in Oregon's mountains until April 1.

"We certainly are not going to make up our current deficit. But a wet spring accomplishes much the same thing because it's coming closer to demand."

Timing is the key for this season, Taylor said. Oregon needs to receive the water just prior to demand. And demand creeps up as late spring blossoms and municipal and agricultural water use leaps.

The Oregon Drought Council meets Feb. 22 to discuss water supplies. Comprised of state and federal representatives, the council will assess the issues and then advise Gov. Ted Kulongoski. It appears several counties are already preparing to ask the governor to declare drought emergencies in their regions, Taylor said.

While the winter of 2004-05 has been dry, it's far from lows recorded in 1976-77, the worst since records have been kept. From October 1976 through January 1977, 5.1 inches of precipitation were recorded in Corvallis - 18.75 inches below average, Taylor said.

The second worst year was 1891 when 9.42 inches of winter precipitation was recorded in Corvallis.

In 2001, the fourth driest year on record and the most recent dry year, 10.92 inches of winter precipitation fell in Corvallis. The winter was followed by a very dry spring with only 7.49 inches recorded.

"That was the year that Detroit Reservoir was virtually empty," Taylor said.