At a Glance

Multiple winter storms have crippled travel in Portland since early December.They've also had one of their coldest winters on record so far.

With yet another round of snow and ice moving in to kick off the month of February, Portland, Oregon's argument as the U.S. city most tired of winter this season is becoming stronger.

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We understand this sounds odd.

"Isn't it much colder in parts of Alaska and North Dakota?" you might be asking. "Hasn't there been feet of snow in California's Sierra or Michigan's Upper Peninsula? Isn't Portland near the Pacific Ocean?"

Yes, that's all true, but compared to an average winter, Portland might be the most miserable location so far.

Hear me out on this.

Five Storms in Over Five Weeks

During some winters, certain areas become punching bags as stubborn patterns lock in for weeks, if not months. Probably the best recent example was , that included Boston.

Over about a five-week period from December through mid-January, five separate winter storms plagued Oregon's largest city.

Winter Stormjust missed Portland, but dumped 20 inches of snow near Bend, Oregon, and led to some .

was an unexpectedly crippling snowstorm. The city's, Jupiter led to abandoned vehicles on snow-choked roads.

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Tree branches, broken from the weight of heavy snow, are scattered on the ground of the park blocks across from the Portland Art Museum in Portland, Ore., Wednesday, Jan. 11, 2017.

(AP Photo/Don Ryan)

On average, Portland sees measurable snow four days a year. Through the end of January 2017, the "City of Roses" already had five such days this winter.

Following 8 inches of snow from at the National Weather Service in Portland, at least 1 inch of snow remained on the ground from January 10 through 17, a streak of 8 straight days.

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While you wouldn't bat an eye about this streak in, say, Minneapolis or Caribou, Maine, NOAA's ACIS database said there were only six longer streaks of at least 1 inch of snow on the ground at Portland International Airport or the NWS office, where official data is now taken, dating to 1940.

29 days (Jan. 13 - Feb. 10, 1950)20 days (Jan. 20 - Feb. 8, 1949)13 days (Jan. 20 - Feb. 1, 1943)12 days (Jan. 27 - Feb. 7, 1956)10 days (Dec. 29, 1968 - Jan. 7, 1969)9 days (Dec. 19-27, 2008)

Portland averages just two days each winter with at least 1 inch of snow cover.

Cold Streak

Given the number of winter storms, it's no surprise the winter has been much colder than usual for this somewhat maritime climate.

The first 18 days of 2017, and 28 of 31 January days were colder than average.

Snow and ice cling to tree limbs as downtown Portland, Ore., is reflected in the Willamette River under blue skies, Thursday, Jan. 12, 2017.

(AP Photo/Don Ryan)

Going back further, 52 of 59 days from December 4 through January 31 were colder than average.

, according to the Southeast Regional Climate Center (SERCC).

The first two months of "meteorological winter" - December through January - ranked as the .

Using a combination of snowfall, snow depth, and days with highs that fail to rise above freezing, the , a winter misery index for several cities in the U.S. so far this winter.

While there is no data available for Portland, the MRCC has calculated an "extreme winter-to-date" in several Northwest cities, including Redmond, Oregon, Yakima, Washington, and Boise, Idaho.

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Plot of the Accumulated Winter Season Severity Index (AWSSI) for the winter season-to-date through January 16, 2017, for Redmond, Oregon, indicated by the black line. The purple-shaded area of the graph indicates what AWSSI values are considered "extreme" for the season-to-date. The yellow-shaded area would be considered average.

(Midwest Regional Climate Center)

Why So Harsh a Winter?

Just 60 miles east of the Pacific Coast, it's usually no problem for milder, Pacific air to surge into the Portland metro area ahead of Pacific storms, shoving any cold air out of the way. This is why Portland averages only 4 inches of snow a year.

How cold air occasionally gets drawn into Oregon's Willamette Valley, including the city of Portland.

Occasionally, Arctic high pressure plunging south out of western Canada is so strong and deep that it doesn't simply bank against the eastern slopes of the Cascades, but squeezes through the Columbia River Gorge, which forms much of the border of Oregon and Washington.

In these cases, the cold air surges on strong easterly winds into the city of Portland, plunging southward into the rest of the Willamette Valley as far south as Eugene, or can even surge westward to the coast over the coastal ranges.

As discussed, this has been happening a lot this winter.

When this happens, cold air can get stuck in the valley for an extended time. Some Pacific frontal systems aren't strong enough to dislodge the cold Willamette Valley air.

Sometimes, these weaker systems simply reinforce the cold air supply from the Columbia Gorge. As a result, moisture overrides that cold air to wring out snow, sleet or freezing rain.

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Combine this persistent, pervasive cold air with an active western storm track, in contrast to recent past years dominated by a jet-stream blocking dome of high pressure, and you have a rough winter for the Northwest.

Recently, there's been a bit of a feedback loop in that the heavy snowpack, by local standards, fromhasn't allowed temperatures to warm up much. This raises the concern for ice from.

With apologies to places also hard hit so far, such as Bismarck, North Dakota, Oregon's largest city has earned the "worst winter" title so far.

Jonathan Erdmanis a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7.

MORE ON WEATHER.COM: Winter Storm Jupiter

An Iowa Department of Transportation snow plow slid off the road Monday morning. (Twitter/Iowa State Trooper Jon Stickney)