Some of the regional highlights:
- December 4-11 arctic outbreak:
Top tier airmass for early December, regionally it was the 2nd most impressive on record in the December 4-9 period behind 1972 and ahead of events like 1880, 1909, 1956, and 2009.
NWS Pendleton tabulated 24 daily record lows tied or broken between December 4-9, highlights include monthly record of -27 at Meacham (keep in mind they have gaps in data set). Seneca fell to at least -28.
EUG's 2nd coldest 5 day period on record, with -10 on December 8 being their 2nd coldest temperature on record and the coldest temperature west of the Cascades since December 8, 1972. Their 7 consecutive highs below freezing tied 1978-79 for the 2nd longest stretch in Eugene since 1892.
Corvallis fell to 2 in the city and 0 at the airport. Their coldest since 1972's low of -7.
Portland's 5 consecutive highs below freezing was the longest stretch of subfreezing highs since December 1990.
Several locations shattered records and approached monthly records. Locations with their 2nd highest January temps on record included Medford at 70, North Bend, OR at 73, Government Camp, OR at 63, and Paradise, WA at 62. Yakima set a daily record with 61 on 1/17.
- February 5-10 arctic outbreak
Greatest post February 4 airmass since 1936 for many spots in the region, including most of northern OR, southern WA, northern ID, and western MT.
Astoria's high of 29 on 2/6 was their coldest on record for so late in the season, back to 1892.
Portland's 4 consecutive highs below freezing from February 5 to February 8 is the latest such an occurrence has happened there since 1936. Since 1871, only February 1936 had a 4 day consecutive freeze stretch start at a later date in Portland.
Historic snowstorm in western OR and WA between February 6 and February 9, with snow depths reaching 6" or more from northern Cowlitz County, WA to southern Lane County, OR on February 8. Snow depths peaked around 14" on February 8 in the Corvallis/Albany area, making it the greatest snowstorm since January 1969 for that particular area.
A remarkable late season continued with a near miss at the end of February for the region.
NW WA and SW BC had their most significant snowstorm since December 2008 and in some cases November 2006. Most places totaled over 10", making it the most significant individual February snowstorm since February 1937 for this particular part of the region.
Historic snows in the NW interior. Missoula, MT had their snowiest modern February on record (since 1948) with 40.2", shattering their modern record by 20" and coming very close to February 1936's 43".
Another huge airmass that clipped the region, delivering historic cold to the interior NW.
Spokane's high of 19 on March 2 was only the 4th occurrence on record of Spokane having a <20 high in the month of March.
Further to the east, western MT got absolutely clobbered for the 3rd time in less than a month. The high of 5 at Missoula on March 1 set a new monthly record for the coldest daily max temp, breaking the March 1906 record of 7.
The Willamette Valley had its coldest winter since 1992-93, with south and central parts of the valley also having their snowiest winter since 1992-93.
Eugene's 10 subfreezing highs was the most since 1978-79's 11 at that location.
Portland's 9 subfreezing highs was the most since 1985-86's 10.
Portland had two separate events with 4 or more consecutive subfreezing highs. The first time that has happened there since 1968-69.
The winter was marked by relatively frequent arctic intrusions, ridging, drought, and by very sharp temperature and snowfall gradients across the greater PNW region. There was a distinct lack of onshore flow for the vast majority of the winter.
The high temperature gradients across OR in early February and across ID and WA in early March were among the most extreme in recent memory. Similarly, the three major I-5 corridor snow events this winter were all aimed at different parts of the region and all failed to deliver a single widespread, regional snow with an arctic cold front or overrunning warm front.