OREGON STATE UNIVERSITY

2012 weather: Bookend wet spells sandwich summer drought

12/28/2012

CORVALLIS, Ore. – 2012 will likely go down as the warmest year on record for the lower 48 states, but it may be remembered just as much for its extreme events – and Oregon was no exception.

Though the state didn’t experience anything like super-storm Sandy or major blizzards that paralyzed communities, it did experience a pronounced summer drought, sandwiched by “atmospheric river events” that drenched Oregonians in January and late November.

Kathie Dello, deputy director of the Oregon Climate Service at Oregon State University, said the impacts from the three phenomena were significant.

“The state was really dry during the July to September period and it really extended into October,” Dello said. “In fact, it was the second driest summer period on record, which made it a big year for wildfires. Oregon (1.26 million acres) was second in the nation to Idaho (1.54 million acres) for most acres burned and many private woodland owners had to close their lands to hunters until mid-October because of fire danger. That doesn’t happen often.”

“The two wet weather events affected western Oregon to a great extent, and caused some fairly serious flooding,” added Dello, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “There were also some rather damaging windstorms.”

One series of storms in January caused major flooding in the Willamette Valley and another series in late November soaked the southwestern portion of the state. These bookend wet spells made the year wetter than normal in western Oregon, though eastern Oregon ended up drier than average. Statewide records go back 118 years.

With a couple of days left in the year, Corvallis is likely to close 2012 with the fourth wettest year on record, with 58.72 inches of precipitation through Dec. 27. The average over the past 30 years has been 42.71 inches. Totals of other Oregon cities, with data gathered in part from the National Weather Service in Portland, include:

  • Medford has received 26.67 inches through Dec. 27, well above its average of 18.35 inches. On November 29, the town received its first rainfall of more than two inches since 2005.
  • Portland has logged 50.43 inches in 2012, fourth highest on record, and well above its average of 36.1 inches.
  • Salem is in the midst of the seventh wettest year on record with 54.38 inches; its average over the past 30 years is 39.67 inches.
  • Astoria has received 91.01 inches, eighth most on record, and more than 23 inches above its average of 67.53 inches.

“Almost all of the wet weather records are from 1996, when the state experienced some rather spectacular flooding,” Dello said. “That was a ‘100-year flood event’ and the records back it up.”

Corvallis had 73.21 inches in 1996; Portland was at 63.20, Salem at 66.96, and Medford at 31.41. Astoria was one of the few places that didn’t peak that year. Its record year was 1950, when it got 113.34 inches.

The chaotic weather in 2012 was fitting in a way – this coming winter is the first time since 2003 that the western United States wasn’t affected by either El Niño or a La Niña conditions. El Niños typically result in warmer and drier winter weather; La Niñas are usually wetter, as it was in January, which was on the tail end of last winter’s La Niña.

“We are neither, for the first time in almost a decade,” Dello said. “Officially we are ENSO-neutral, or what some people call ‘La Nada.’”

Weather-lovers can learn more about Oregon weather by following Dello on Twitter at: www.twitter.com/orclimatesvc. The state is also looking for volunteers to collect precipitation data. For more information, go to http://www.cocorahs.org/.