Extreme heat warnings are in effect across large portions of the United States this week, as an unusual weather pattern drives record-breaking temperatures. In Billings, Montana, the mercury reached 111°F (43.9°C) on Sunday, the hottest day ever recorded in the city. Salt Lake City, Utah, also tied its all-time high of 109°F on the same day. Boston has experienced more 90°F days than average, according to NPR station WBUR-FM.
Heat Dome Traps Hot Air Across Regions
The high temperatures are attributed to a so-called “heat dome,” a phenomenon where high atmospheric pressure traps heat over a region for an extended period, suppressing clouds and storms. Cara Schulte, a researcher at Climate Rights International, explained that this creates hot, dry conditions. The lack of nighttime cooling in parts of the Midwest and Northeast compounds the daytime heat, increasing the risk of heat illnesses and cardiovascular strain for vulnerable groups such as the elderly.
Wildfires Rage in Canada and the US
The heatwave coincides with a deadly wildfire season. In late June, three firefighters were killed battling a blaze along the Colorado-Utah border. This week, a helicopter pilot responding to a fire in Colorado died after his aircraft crashed under unknown circumstances. According to the National Interagency Fire Center, dozens of wildfires are currently burning in states including California, Oregon, Colorado, Utah, Minnesota, and Idaho.
Heavy smoke from over 100 wildfires in Canada has given Toronto the worst air quality in the world, with winds pushing pollution south into the US. Warnings about dangerous, unhealthy air on Wednesday extended from Minnesota to New York City, where unusually hot summer temperatures were also expected.
Health Risks from Combined Heat and Smoke
Tyler Hasenstein, a meteorologist with the National Weather Service in Chanhassen, Minnesota, advised residents to stay indoors to avoid both smoke and extreme heat. “Those two things coinciding with each other is not good from a health perspective,” he said. Severe drought and heat have already led to a busy wildfire season, with fires scorching about 3.6 million acres of land to date, according to the National Interagency Fire Center.
Trevor Stankiewicz, another researcher at Climate Rights International, noted, “Heatwaves like this one dry vegetation across the west, turning them into kindling, until a single spark can become a climate disaster.” Dan Westervelt, associate professor at Columbia University’s climate school, added that severe drought combined with heat in Canada and the US has created “a perfect storm for really dry conditions to provide a lot of fuel for these wildfires to burn.” Research shows that warming temperatures from burning coal, oil, and gas are making fires more frequent and intense.
Evacuations in Minnesota Wilderness
In far northeastern Minnesota, rangers are warning that the Boundary Waters Canoe Area Wilderness is closed due to about 17 lightning-caused fires burning around the vast, canoe-accessible area. The area was closed Tuesday, and rangers estimate that 6,000 to 10,000 people are still inside the 1.1-million-acre (445,000-hectare) wilderness, nearly the size of Delaware. Joy VanDrie, Superior National Forest spokesperson, said, “It’s an arduous job,” describing how rangers and campers must canoe for hours or carry their boats over land to evacuate.
Forecast and Safety Tips
The National Oceanic and Atmospheric Administration forecasts heat hazards to persist through next Monday, with California and several upper Midwest states at risk of dangerous heat levels for the first half of this week. High temperatures are expected to blanket southern areas later in the week. Officials urge the public to watch for symptoms of heat-related illnesses, such as heat exhaustion (profuse sweating, clammy skin, fatigue) and heatstroke (slurred speech, rapid pulse, body temperature over 103°F), which is a medical emergency.
