Excessive Heat Watches Continue Throughout Pacific Northwest

After a record-breaking heatwave scorched swathes of the Pacific Northwest over the weekend, excessive heat watches continued to be in effect for regions stretching from Northern California to British Columbia, Canada.

The heatwave, which climate scientists say is a one in a 1000-year event or greater, is the hottest weather event ever recorded. Over the last 30 years on average, heat waves have caused more deaths nationally than any other form of weather event including hurricanes and tornadoes, according to National Weather Service data.

“Yesterday, Portland International Airport reported 112 ℉ [44.4 ℃] far exceeding any historical precedent,” Robert Rohde, lead scientist of Berkeley Earth, an independent non-profit organization focused on environmental data science, said in a Tweet. “That would be like Dallas reaching 130 ℉ [54 ℃] or Madrid at 120 ℉ [49 ℃]. Today, Portland is forecast to be even hotter at 114 ℉ [45.5 ℃].” 

This stretch of extreme heat is being caused by a vast “heat dome,” or a huge pocket of hot air trapped under a high-pressure system combined with stronger-than-usual winds brought on by La Niña, according to the National Oceanic and Atmospheric Administration. Studies indicate that severe heat events are estimated on average to be between three and five degrees hotter than they otherwise would be without the impact of decades worth of greenhouse gases released by the man-made burning of fossil fuels.

On Sunday, temperatures reached 112 degrees in Vancouver, Wash., 115 degrees in The Dalles, Ore., and 116 degrees in Lytton, British Columbia. All of these represent a record high in their respective localities, and the temperature recorded Sunday in Lytton represents the highest temperature recorded in Canada in any month.

“I estimate that Portland International Airport reaching 112 °F [44.4 °C] is roughly 4.3 standard deviations above the historical mean,” Rohde said on Twitter. “Historically, we’d expect a deviation that large to happen on roughly one day out of every 350 years. But things aren’t the same anymore. Climate change is loading the dice. By adding a few degrees of warmth to the climate, historically improbable events are suddenly occurring with alarming frequency.”

Seattle’s temperature climbed to 104 degrees Sunday, topping its previous record of 103 degrees set in 2009. However, Seattle’s temperature was forecast by meteorologists to exceed its own record-setting high on Monday, potentially topping out at 109 degrees.

Likewise, Portland is expected to break its own day-old heat record with a high of 115 degrees on Monday. Prior to the weekend surge in hot weather, Portland’s previous record high stood at 107 degrees set in 1981.

“It’s critical that people do what they can to avoid the heat as temperatures get to the level where they can cause serious health problems,” Richard Leman, public health physician at the Oregon Health Authority said in a written statement. “Temperatures that get above 100 are nothing to take casually. These conditions can be extremely dangerous if we don’t take care of ourselves.”