Heat waves, floods of rain from the tropics and now a record-breaking cold snap.
West Washington’s weather last year has been one of extremes, and much of it has turned out as climate scientists have been predicting for decades. For three local meteorologists asked to weigh the most significant weather of the year, the record year was not unexpected.
“I don’t think you need a rocket scientist to see where this is going,” said Justin Shaw, who writes the Seattle Weather Blog.
Joe Boomgard-Zagrodnik, a former Washington State University meteorologist who now works in the private sector, said the year was the epitome of forecasting by climate scientists.
Here are the weather events Shaw, Boomgard-Zagrodnik, and Logan Johnson, senior meteorologist at the National Weather Service in Seattle, listed as the most extreme this year:
Strong wind and rain in January
The first of the extreme weather events listed by Johnson occurred in January. A period of significant storms and successive atmospheric river events flooded dozens of rivers. Many landslides have also been observed.
On January 12th and 13th, winds ranged from 50 to 70 miles per hour over the lowlands and up to 80 miles per hour in the mountains. These included gusts of 58 mph at Seattle-Tacoma International Airport, 64 mph at Whidbey Island, 56 mph in Tacoma, 48 mph in Everett, and 49 mph in Bellingham.
These winds toppled trees and resulted in blackouts, with more than 500,000 customers in the Puget Sound region running out of power during the height of the event.
Heavy snowfall in February
While there were a few minor snow events in the Seattle area in the winter of 2020/21, Johnson said the most significant came from February 12-14.
About 6 to 12 inches of snow fell from the Everett area south of Oregon, with Portland receiving 9 inches of snow.
A significant amount of freezing rain ensued in some areas, Johnson said.
Sea-Tac recorded 8.9 inches of snow on February 13, making it the snowiest day of February at the airport and the snowiest day in Sea-Tac since December 31, 1968.
Record heat in June
Shaw, Boomgard-Zagrodnik, and Johnson all said the heat wave in late June – when Seattle hit a record-breaking 108 – was astonishing.
“That was an event that exceeded anything we had ever seen before, and it rewrote the narrative of what is possible in the Pacific Northwest,” said Boomgard-Zagrodnik. “It was amazing.”
The unprecedented heat wave brought record temperatures in several states and parts of Canada.
June 24-28 brought five consecutive days in Seattle to or above 90 degrees, including three consecutive days of 100 degrees or more. Seattle recorded the hottest temperature ever on June 28, peaking at 108 degrees.
Olympia hit 110 degrees that day while Everett hit 100 and Tacoma hit 105.
Numerous fires have been reported across the region, along with infrastructure impacts from kinks in roads and railways, and hundreds of people have died across the region, Johnson said.
In retrospect, it seems that 2017 “was the year the switch was flipped,” Shaw said. In the past five years, all but 2019 brought record-breaking heat, unprecedented forest fires in the northwest, and smoke in Seattle, he said.
The wettest fall on record
Incredible, said all three meteorologists, was our rainfall with bomb cyclones, one atmospheric flow after the other, and the wettest meteorological fall in Seattle’s recorded history.
While fall is usually a wet time of year, fall 2021 was special.
Narrow clouds of moisture from the Pacific tropics known as atmospheric rivers brought torrential rains that forced evacuations, caused power outages, landslides and severe flooding, and caused Governor Jay Inslee to declare a severe weather emergency.
SeaTac recorded over 19 inches of rain between September 1 and November 30, compared with 11.81 inches for a normal fall, Johnson said.
Bellingham saw its wettest fall on record with 23.55 inches of rain (breaking the previous 1990 record by more than 6 inches). A coastal weather observatory near Forks measured over 67 inches of rain this fall.
November-December atmospheric rivers
As part of the wettest fall ever, November was a record month in itself in many areas.
November is usually the wettest month of the year for Seattle, which made this year’s 10.26-inch total length this month even more remarkable at Sea-Tac. A number of atmospheric river events during the latter part of the month brought heavy rainfall and very high snow depths (meaning snow accumulated only at high altitudes) to west Washington, Johnson said.
Two consecutive weeks of rain, beginning on November 18, left many mountains in the region bare by early December and contributed to widespread mudslides and flooding.
Significant flooding has been recorded on the Skagit and Nooksack Rivers in Whatcom County and adjacent parts of British Columbia, displacing hundreds of residents from their homes in communities along the rivers including Everson and Sumas.
Mount Vernon experienced near-record flooding, with some of the highest river levels on the Skagit since the 1990s. Floods and landslides had a significant impact on the roads in the area, closing off parts of Interstate 5 south of Bellingham, as well as many roads on the Olympic Peninsula.
“They said the summers would be warmer and drier and the winters wetter, and that is exactly what happened,” said Boomgard-Zagrodnik.
Cold snap at the end of December
An Arctic explosion in the last week of December brought some of the coldest daytime temperatures ever to the Puget Sound area, as well as more snow than usual. The winter weather covered the streets with snow, causing vacation travel interruptions and power outages.
On December 26th, Sea-Tac recorded the low of 20 degrees, surpassing the previous low temperature record of 22 degrees for that date, which was set 73 years ago in 1948.
December 27th marked a second day with record-breaking lows. The lowest temperature in Sea-Tac was measured at 17 degrees, beating the 1968 record of 20 degrees for the date by three degrees.
Although no daily record was set on Dec. 28, temperatures remained below freezing, which is the longest sub-freezing time since 1998, Shaw said.
By December 29, some parts of the Puget Sound region had already exceeded their average snowfall for the month. Seattle recorded 3.9 inches of snow, more than double the city’s normal December figure.