Pheno Update: Winter’s Final “Shadow”

Pheno Update: Winter’s Final “Shadow”

March 2017 has been extremely wet across the Pacific Northwest, but it hasn’t been particularly cold. My forecast for strong, 2009/2012-esque cold departures ended up busting completely, and temps are running very close to normal for the month.

HOWEVER…our extremely cold and snowy winter has continued to cast its shadow over early spring. Cold temps in January and February meant that the tree sap and flower buds weren’t able to get the kind of “jump start” they can pull off in average to warm winters. Despite being pretty close to average temps for 3 weeks now, early spring vegetation in The Dalles is still running a solid 10 to 14 days behind its “pheno average”.

Photos taken between March 23 and 25 show the evidence: no flowering plum or apricot yet, and very little magnolia save a couple early-bird specimens that were trying to peep out slightly. Two years ago all these flowers began to unfurl in late February, and were in full bloom by the first week of March. So in spite of the average March temps, these plants are running a FULL MONTH behind their 2015 phenology.  Put another way…that’s probably the equivalent amount of difference you’d see if you drove 500 miles north or south during the springtime.

Photos from late Feb. 2015:

 

Versus late March 2017:
Obviously…places that were generally “less cold” last winter (like Salem and Eugene), we can expect that their spring vegetation would be somewhat less delayed. On Sunday, March 26 I was on a trip to Salem. In addition to impressive ice damage to trees between Cascade Locks and Troutdale, I couldn’t help but watch the neighborhoods for signs of more “advanced” phenology than existed in The Dalles.

At some point around Gresham, I noticed the first sign of a peach/plum that was starting to peep out slightly. Then once we got south of Clackamas Town Center and especially south of Oregon City, the pink plums were in full bloom! Remember that we had a LOT of cold east wind coming through the Gorge into the Portland Metro area last winter, especially in January and early February. The result is that trees and bulbs are visibly more delayed near the mouth of the Gorge (i.e. Gresham and Troutdale) than they are in places further removed from the east wind, such as Wilsonville, Salem, etc. Probably at least 4-5 days’ worth of difference, maybe more if you’re using downtown Troutdale as your reference point.

All of these were taken in or near Salem:

 

I didn’t get any photos of the cottonwoods near Gresham and Troutdale, but they still had NO visible green. Interestingly, while I didn’t get a good chance to photograph any magnolias, I noticed somewhat less variability between The Dalles and Salem in general. They were out a bit more in Salem and Oregon City, no doubt – but the difference was pretty subtle. All in all, this trip turned out to be a field day for my inner pheno geek!

One more thing: during a long walk in Salem in the rain, I was very glad that I had brought an umbrella! The raw damp chill reminded me of a typical winter day in Western Oregon, even though it was early spring. Temps during the midday in Salem were in the upper 40s, with high temps early that evening in the low 50s.
That’s one thing about the different climates that can be confusing: the Willamette Valley experiences the seasonal cycle differently than the eastern Gorge does, due to the extra rainfall and more maritime influence in general. A typical drippy midwinter day in Salem may be 45 degrees, while it’s 35-40 in The Dalles. By mid/late March it’s still not unusual at all to have a cloudy, wet day in Salem with high temps barely in the low 50s – not much better than that average winter day outlined above. But in The Dalles, that exact same early spring day might bring 55-58 degree temps with west wind instead of east. (In other words: far different from midwinter!)

And then The Dalles swings well ahead of Portland and Salem, temperature-wise, as we go through April and May. So while our winters may be pretty cold and gloomy, once spring kicks in we REALLY know it. In contrast, Portland/Salem/Eugene in many wetter or cooler years (like this year), it can be kind of hard to tell exactly where winter ends and spring begins. In general, don’t let the slightly earlier daffodils and plum blossoms fool you: the onset of “West Side Spring” is nothing to get excited about. The flowers will have barely started blooming, when the epicenter of nice weather shifts to places east of the Cascade crest…

Leave a Reply

Your email address will not be published.