‘Been little relief’: Boise breaks heat record on Tuesday as Idaho continues to bake
Boise broke a heat record on Tuesday and is expected to set another on Wednesday as an unusual stretch of hot weather continues to grip the region, according to the National Weather Service.
Tuesday marked the ninth straight day in Boise of temperatures topping 100 degrees, tying a record first set in 2003 and matched in both 2006 and 2015, according to NWS meteorologist Stefanie Henry. The high on Wednesday is forecast to be 102, leaving Henry to tell the Idaho Statesman that she is “pretty confident” the city will set a new record.
On Tuesday, Boise beat the all-time high for July 6 of 105 when temperatures rose to 106 by midafternoon, Henry said.
The high temperatures are being caused by a dome in the Northwest that has been pushing hot, dry air in a clockwise direction, Henry said. Even North Idaho has been hit hard, with temperatures of 104 in Lewiston on Tuesday and 94 in Coeur d’Alene. It was 97 in Spokane, which last week had several days of 100-plus temps.
In June, only five days in Boise had an average daily temperature that was below normal, Henry said. So far in July, there have been none.
To calculate the normal temperatures, the weather service uses data from 1991 to 2020, Henry said. The 30-year accumulation of data, which is referred to as Climate Normals, is used at locations across the country to provide more up-to-date, relevant data on the climate in a particular region.
In interviews, multiple scientists have said that the region’s extra-hot and dry weather is attributable to a changing climate largely caused by human emissions of fossil fuels. On July 2, Mojtaba Sadegh, an assistant professor of civil engineering at Boise State University who studies hydrology, told the Statesman that the intensity of this heat wave is “without a doubt” connected to climate change.
In an email, Jennifer Pierce, director of Idaho Climate Literacy Education Engagement & Research at Boise State, said, “This heat wave is the planet’s response to increased CO2 in the atmosphere from burning fossil fuels.
“Scientists have known for over a century that increased carbon dioxide in the atmosphere traps heat and strengthens the Earth’s greenhouse effect. In the Western USA, this results in increased severity of drought and increased size and severity of wildfire.”
Henry said temperatures at night have been dropping less than they normally do, offering less respite. So far this month, daily low temperatures have been in the mid-to-low 70s.
“A lot of the impact of the heat wave we’re having right now is the high low (temperature),” Henry said. “There’s been little relief.”
On Tuesday afternoon, the Idaho Department of Environmental Quality issued a moderate air quality advisory for Wednesday in the Treasure Valley, according to a release. The department asked residents to limit driving trips and not burn materials outside, both of which contribute to poor air quality.
WEATHER RELIEF LATER THIS WEEK
On Thursday afternoon, a front of cooler air from the northwest could reduce temperatures slightly in the region — but only for a couple of days, as the heat dome gets pushed farther south.
“There’s a weak cold front that will pass to our north and that will bring slightly colder temperatures,” Henry said.
The expected high on Thursday is expected to be 98 — barely snapping the streak of 100-degree days — with a much more pleasant low of 62. The high on Friday is also forecast at 98 for now.
But once that slightly cooler air abates, temperatures are going to climb again. The highs on the weekend are expected to be 103 Saturday and 105 Sunday.
The long stretch of extreme heat “definitely has an accumulative effect on people, animals and vulnerable groups,” Henry said.
This story was originally published July 6, 2021 at 5:18 PM.
