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Here comes La Niña

The forecast: Cold, gray, wet and miserable
by: Shada Tice An October view of Mount Hood from Trillium Lake gives little away about the heavy snowpack predicted for this winter because of what meterologists are saying could be another La Nina winter in the Pacific Northwest.

Now that the rain and cooler temperatures have arrived, many are dying to know: What's in store for the next nine months?

The National Oceanic and Atmospheric Association's Climate Prediction Center says the weather phenomena known as La Niña will be back for a second consecutive year. That means the sea-surface temperatures near the equator are cooler than average, which tends to bring more precipitation.

In other words, hold on to your hats: The Pacific Northwest is about to see another wetter and colder winter that likely will extend into spring.

That's good news for skiers, bad news for gardeners.

'Last year was a strong La Niña episode with another forecast for this year,' a phenomenon called a double tip La Niña, said Tyree Wilde, warning coordination meteorologist for the National Weather Service. 'I think for us it's going to be a very similar winter to what we experienced last year.'

But it could be slightly better.

'Typically the second La Niña is not as strong as the first one,' Wilde said. 'And last year was a very strong one, one of the strongest ones we've had.'

More rain, mountain snow

Last year, the Portland-metro area saw two cold snaps - around Thanksgiving and then in late February - that weren't as memorable as the snow and ice storm of 2008, but nonetheless had everyone glued to the weather report.

As is typical for a La Niña year, it was wetter than normal. This past year Portland saw 46 inches of precipitation, compared to the annual average of 37. The last time the region saw such an active winter was in 1994, 1995 and 1996, which brought 43, 55 and 59 inches of rainfall, respectively.

With all the rain, river flooding and windstorms are more likely in a La Niña year. In January, the Sandy River - swollen from heavy rain and snowmelt - washed out part of Lolo Pass Road, leaving about 250 people stranded.

Skiers might also recall that flooding rain closed ski resorts in January after nine inches of rain fell on Mount Hood in 24 hours, which is a rarity.

La Niña also brought the giant windstorm or 'Great Coastal Gale' on the Northern Oregon Coast in 2007 - the strongest in the region since 1962's deadly Columbus Day Storm.

'And sometimes it's cooler than normal,' Wilde said.

Last winter, the mountains saw great snow packs with minimal accumulation on the valley floor. The last La Niña winter before our forecasted double dip was in late 2007 to early 2008, which also was a massive snow year in the Cascades.

'Skiers love La Niña,' said Kathie Dello, deputy director of the Oregon Climate Center at Oregon State University. 'People ask if they should buy a season pass. I would consider it.'

But La Niña is not to blame for the 'Snowpocalypse' of December 2008, resulting in the third largest snow year in Portland since 1940, Wilde said.

By then, the system had moved from a La Niña into more neutral conditions.

Each weather event - be it a La Niña or the more rare El Niño, when it's warmer and drier than normal - typically lasts nine to 12 months and cycles in and out every three to five years, interspersed with periods of neutral years.

Neutral anything but

But don't be fooled by the harmless sounding name.

Neutral years are typically marked by more lower elevation snow in the valleys and really strong significant storms. Think ice storms and big winds on the coast, Wilde said.

'We have a tendency to get more of the high-impact weather events during those years. And that's what we were in during that big snow storm,' he said.

Todd Felix, emergency management specialist for the city of Gresham, said those neutral years, or slack years as he calls them, are the biggest weather wild card.

'That's a lot of time when we get the most unpredictable whether,' Felix said.

And it looks like there's a strong possibility such a slack year could hit next year. There's been just one three-year La Niña in the past 50 years. Usually after a double dip La Niña, an El Niño pattern returns or the climate falls into that fearsome neutral period.

Considering the fact that Gresham declared a state of emergency during the last slack year's snow and ice storm, East County residents perhaps should worry less about this upcoming winter and more about the winter of 2012-13.

'That was such an usual event,' Felix said of the Snowpocolyse and state of emergency. But it's one he won't soon forget.

Felix had only two days off during the entire month of December when the storm hit. And he spent those two days trapped at his home in rural Clackamas County after a landslide wiped out the road to his house.

Plus, an electrical fire burned his neighbor's house to the ground after the structure was wiped off its foundation.

But the silver lining comes in the form of lessons learned from the Storm of 2008.

'We learned a lot,' Felix said. Since then, the city has teamed up with TriMet to make sure Gresham's snow plow routes match TriMet's bus routes.

Gresham and Multnomah County officials also compared plow maps to make sure they aren't doubling efforts and plowing the same road, or missing streets entirely.

The city also has compiled information on private service providers, such as road graders, heavy equipment operators and other equipment vendors. Now the city knows who is willing to loan or rent equipment - or any other ways they can help - during a disaster.

Better next spring?

Dello, of the Oregon Climate Center, said that in her opinion, La Niña packed a bigger punch this past spring than winter, since March through May were all anomalously wet.

In addition, May through July were the coolest months on record, according to the National Climatic Data Center. Conditions wreaked havoc on local fruits and crops: The U.S. Department of Agriculture recently declared Washington County, among others, to be a natural disaster area because of a 30 percent or more drop in crop values.

'The longer, colder and wetter the spring, it's especially challenging for the stone fruits like plums and cherries - they get fungal disease,' said Katy Kolker, executive director of the nonprofit Portland Fruit Tree Project. 'When there's more moisture and cold in the spring, the fungal disease runs rampant.'

The trees produce less fruit, fall into poor health, experience delayed ripening and sometimes don't ripen in time for harvest, Kolker said.

But she sees the big picture: 'It's sort of the nature of what we do. We're always at the whim of nature in terms of how much fruit there's going to be.'

With all of this in mind, Fox 12's Chief Meteorologist Mark Nelsen is optimistic.

'You just survived the coolest late spring in Portland's history,' said Nelsen, a Corbett resident. 'It can only be better next spring.'

Sandbag station opens Nov. 7

Just in time for those La Niña rains to begin falling, Gresham's free, fill-your-own sandbag station is set to open on Monday, Nov. 7.

The station is open from 8 a.m. to 4 p.m. and is located at the city's operations center at 2123 S.E. Hogan Road. Sand, shovels and bags are provided for free to Gresham residents for home or private use only - namely to protect property from flooding or rain runoff.

Sandbags are not available for commercial/contractor consumption. Citizens are responsible for the sandbags after use; public works crews do not dispose or retrieve them. If rainwater on the street is creating a hazard or localized flooding call the operations center at 503-618 -2626.