NOAA weather warnings covered large swaths of the United States this week as a heat dome drove record temperatures and unhealthy air. Tyler Hasenstein, a meteorologist with the National Weather Service in Chanhassen, Minnesota, said the best advice was to stay indoors to avoid both the smoke and the extreme heat.
Billings, Montana, reached 111F on Sunday, the hottest day in its history. Salt Lake City, Utah, hit 109F the same day, and the heat did not subside at night in parts of the midwest and north-east.
National Weather Service warnings
Warnings about dangerous, unhealthy air on Wednesday extended from Minnesota into New York City. Wildfires were burning in California, Oregon, Colorado, Utah, Minnesota and Idaho, while more than 100 wildfires were burning in Canada.
Tyler Hasenstein said, "Those two things coinciding with each other is not good from a health perspective" when he described smoke and extreme heat together. The overlap of hot days, warm nights and smoke left some residents with fewer cooler hours to recover.
Billings and Salt Lake City records
Boston has seen more 90F days than average, adding to the run of unusual summer heat across the north-east. Cara Schulte called the atmospheric pattern a "heat dome," and Dan Westervelt said it created "a perfect storm for really dry conditions to provide a lot of fuel for these wildfires to burn."
Trevor Stankiewicz said, "Heatwaves like this one dry vegetation across the west, turning them into kindling, until a single spark can become a climate disaster." In the Boundary Waters Canoe Area Wilderness, about 17 fires caused by lightning led to a closure on Tuesday.
Canada and the US smoke
Toronto had the worst air quality in the world because of heavy smoke from more than 100 wildfires burning in Canada, and fires this year have scorched about 3.6m acres of land to date. Three firefighters were killed in late June while fighting a blaze along the Colorado and Utah border, and a helicopter pilot responding to a fire in Colorado died this week after his aircraft crashed under unknown circumstances.
For residents in the US and Canada, the immediate step is the one Hasenstein gave: stay inside when smoke and heat overlap. That advice is most urgent where warnings, record heat and overnight warmth are all happening at once.
