OREGON STATE UNIVERSITY

The spring of 2011 – when May looked like November

06/01/2011

CORVALLIS, Ore. – Though summer isn’t officially here for another three weeks, climatologists are putting spring behind us – and most Oregonians would say good riddance.

From a climatology standpoint, spring ends on May 31, and surprisingly, this La Niña-influenced spring wasn’t the coldest or wettest on record for most of western Oregon. It may have ranked among the most depressing, however. While it wasn’t often frigid or raining cats and dogs, it simply was not warm or dry very often.

Kathie Dello, deputy director of the Oregon Climate Service at Oregon State University, says 2011 has been “off by about a month.” April, she says, was like a typical March in terms of temperatures and precipitation. May was what April should have been.

“It may have felt like winter, but it’s worth noting that very few daily temperatures and precipitation records were broken in western Oregon over the spring,” Dello said. “Rather, the rain was persistent and the temperatures were almost consistently below average.”

Nevertheless, some things stood out:

  • The Portland Airport recorded the second wettest spring on record with 14.39 inches, just missing the mark set in 1997 of 14.50 inches. It also was the third coldest spring there with an average temperature of just 49.33 degrees. Records at the airport date back to 1948.
  • Portland, in fact, received more rain in April than in January – and maximum daily temperatures were at or above normal only 18 times in the last three months.
  • Corvallis didn’t even crack the top 10 for coldest springs, but it was the fifth wettest overall with 15.32 inches and records there go back to 1889. Minimum temperatures in April averaged 37.3 degrees, which was actually two degrees colder than it was in March.

“Some volunteer spotters reported traces of snow in Deschutes County over Memorial Day weekend, and Big Red Mountain in the Siskiyous has recorded eight inches of new snow in the last five days,” Dello said. “It’s been that kind of a spring and it’s fairly typical of La Niña years. We’ve had a deep low-pressure system anchored over the region for much of the past three months.

“Sometimes, that means a mixed bag of weather,” Dello pointed out. “Eugene has been on the cool side, but precipitation levels were about normal. However, large snowpacks and spring rain have led to flooding in eastern Oregon’s Union, Grant and Wheeler counties, and moderate flooding on the lower Columbia River.”

The weather nationally has been even more chaotic, Dello said. If you draw a line from California to Wisconsin, the weather north of that line has been cooler than normal, while temperatures in the South have been much warmer, as they have in parts of the Northeast.

What’s next? Dello says the NOAA outlook for the next three months concludes there is an equal chance of being warmer or cooler than normal – but that there is a chance of below-average precipitation for June, July and August.

“The bottom line is that it was a cool and damp spring,” Dello said, “but at least we didn’t have to contend with tornados like some of the country.”