‘Slightly lucky’: Boise ties record but misses the worst of scorching Northwest heat
Yes, it’s hotter than heck in Boise and the Treasure Valley. But if you want to beat the heat, don’t head north or west, because it’s worse.
Scorching temperatures dotted the Pacific Northwest and even British Columbia on Monday and Tuesday, as a high-pressure ridge of hot air continued to smother the region. It was a scorching 115 degrees in Lewiston on Tuesday and 110 in Spokane, Washington, for instance.
On Monday, thermometers in Portland hit 116, according to Korri Anderson, a meteorologist at the National Weather Service’s Boise office. It was 117 in Salem, Oregon, and 108 in Seattle. All three temperatures were all-time records. In Lytton, British Columbia, it was 118, the hottest temperature ever recorded in Canada.
But in Boise and much of Southwest Idaho, the heat — while certainly noticeable — wasn’t as bad as first predicted.
So what gives? Simply put, the hot air parked over the entire region flows in a mostly clockwise direction, and the center of it is far enough west and north to spare Boise a tiny bit.
“I think we’re going to miss the worst of it,” Anderson told the Idaho Statesman by phone.
Last week, the weather service was predicting temperatures as high as 110 degrees on Tuesday, but the high wound up being a handful of degrees cooler. The 105 temperature still tied a record for June 30.
“The high-pressure system is not centered right over Boise,” Alejandro Flores, a professor of hydrologic sciences at Boise State University, told the Statesman. “Had the location of that high-pressure system been a little bit off, we could’ve seen the temperatures that we saw in Seattle and in Portland. … Boise got slightly lucky with the location of it.”
The dome of hot air isn’t the only culprit for the soaring temperatures, according to Russell Qualls, Idaho’s state climatologist. He told the Statesman that the extreme drought in much of the region likely worsened this heat wave.
“There’s a coupling between these dry, drought conditions and the warmer temperatures that we’re getting,” he said.
When sunshine hits Earth’s surface, he said, soil moisture evaporates, which helps cool the air. With less moisture in the soil, though, that can’t happen.
Much of Idaho received a lot of snow over the winter and into March, but “the precipitation shut down earlier than normal (and) things began to heat up,” Qualls said.
A CHANGING CLIMATE
Though the Northwest has seen heat waves in the past, Flores told the Statesman that this week’s weather is indicative of a changing climate, which has been contributed to by human emissions of greenhouse gases.
“The heat wave that we’re seeing in the Pacific Northwest is completely in line with what we would expect in a warming climate,” he said. “Climate change serves to increase the duration, the magnitude and the intensity of these kinds of events.”
Though these high-pressure systems often occur during the summertime, “it’s almost never been this early, this intense and this widespread,” he added.
Flores said the combination of scientists’ understanding of climate change plus the uncommonness of such high temperatures over a wide-ranging geographic area points to a meaningful shift.
“Those two things suggest to me that climate change is really juicing the ball in events like this,” he said.
Weeklong heat waves do not bode well for the ongoing drought and for fire season, he said.
“The impact of this particular heat wave will be felt beyond the days in which we have high temperatures,” Flores said. “… We’ve almost certainly depleted all of our snowpack up in the mountains in Idaho. This kind of heat really dries out the soil in the mountains and the plains.”
This story was originally published June 29, 2021 at 5:41 PM.
