Pacific Northwest’s recent winter storm is a study in delays
For the last week, warm moisture building off the Pacific Ocean and heading east via the jet stream toward us, the so-called Pineapple Express, met up with Arctic air pouring south from Alaska and Canada giving us a succession of storms over about a week. We’ve had heavy rain (up to nine inches in 30 hours in some places), massive snow fall in Seattle and the Cascades (several feet in the last three days), hurricane force winds on the Oregon coastal headlands (110 mph), and flooding throughout Oregon and Washington. The storms hit both state capitols: flooding in Salem and power outages in Olympia. It’s all been building for several days, and it’s still going on now that the brunt of the weather is through us and now pounding the Rockies.
All I could think about through this – aside from maybe getting a day off from school – was the system of delays that led to widespread flooding. I know, I’m such a fun-lovin’ guy.
When the phrase “winter storm” enters the Pacific Northwesterners lexicon, we realize there’s a complex system meteorology and geography that are at work. And it will take several days to play through.
Once the Arctic air settles in from up north and conveyor of warm tropical air sends one warm, sopping system after another over the region, snow is on its way. And it’s the stuff of Christmas cards and coffee table books and screen savers. Positively breathtaking landscapes of snow-bent pines and firs, distant peaks shining in alpenglow. And there the snow stays – a stock of water frozen in time.
Then, the warm rains come. Really warm . . . from 20’s to 50’s in 18 hours. And it comes in gobs, two or three inches in a day. That deep stock of water that accumulated as 6″ of snow on streets and lawns and roofs melts away. That one-day delay of extra water stored as snow gives way amid a following heavy rainstorm.
Another day goes by. Freezing levels rise from the Willamette Valley floor to 3,000′ and 4,500′ and all that low to mid-elevation snow, pelted by rain and thawed from warm temperatures, melts and flows downhill along road sides and into streams and creeks and rivers. Several feet of stored water, nature’s freshwater storage, melts away in 36 hours.
I live about 80 feet south of Portland, near the confluence of the Willamette and Columbia Rivers. Much of the flooding reported in the news begins far south of me, near Corvallis and Salem and Aurora. All that water, loosed by warming temperatures and days of rain from the Pineapple Express, flows out of the Cascades and Coast ranges, pouring off the flanks of foothills and into the tributaries of the Willamette River.
The surge heads north from Corvallis. And then to Salem.
Two days after flooding down valley, the crests hit in the Portland area. By then, five days after snow fell in Portland, the big damage was south of us . . . and waters had begun to recede.
Hey. we grow stuff here . . .
What helps me out is that I recall the world’s best hops, best mint, best hazelnuts, and best berries grow right here . . . in all this inundated land. Once in a while, a little flood can do some good, bearing down the mountain all that forest debris and biotic detritus from the fecund Cascade Range layering the Willamette Valley with dark soil for all that growing.
It’s what makes raising a pint on a July night worth all the gloomy wait through winter.
- Twin winter storms slamming Pacific Northwest – CNN (edition.cnn.com)
- Seattle Snow Storm Could Be Worst Since 1985 (blippitt.com)
- Historic winter storm likely to blast Northwest – USA TODAY (usatoday.com)