Both states experienced temperatures that topped their 126-year historical records and helped set the stage for historic wildfires on the West Coast.
“The western half of the contiguous U.S. was warmer than average, with both Oregon and California being warmest on record for the month of September,” says Karin Gleason, a climate scientist with NOAA’s National Centers for Environmental Information.
Both Oregon and California are warming by three degrees Fahrenheit per century, or 0.3 degrees F per decade, she says. Both states topped their records, which date back to 1895.
A new global average temperature record was also set in September, adding to the long-term warming trend. The 20th-century average of 59.0 degrees F was surpassed by 1.75 degrees F.
“The ten warmest Septembers on record have occurred since 2005. But the seven warmest have occurred the last seven years,” Gleason says. “Think about 1880 to the present. Statistically speaking, that’s not by chance.”
Between drought conditions, high wind events, and record temperatures, the West Coast was pummeled with factors contributing to the historic wildfire season, in which some California fires are still burning.
Western wildfires in Washington, Oregon and California are one group of incidents that, so far, tie 2020 with the most billion-dollar weather and climate disasters. The years 2011 and 2017 share the current record with 2020 of 16 events with billion-dollar losses. Five of the six largest fires in California’s history occurred so far this year.
Gleason says historical data indicates with 99.9% certainty that overall 2020 will be within the top five warmest years globally and possibly warmer.
“The statistical outcomes are most likely warmest or second warmest for the globe,” she says.
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