Sweltering air will continue to sweep the region through the holiday, along with ozone advisories.
Thunderstorms and heavy winds around 3 a.m. Tuesday knocked down branches and provided the Twin Cities metro area with a brief break from the sweltering temperatures that are expected to last the entire week.
In northern Minnesota, flash flood warnings were in effect Tuesday morning for Central Aitkin, Southwestern Cass, Central Crow Wing and Southwestern Carlton counties until 8:30 a.m. The National Weather Service estimates that 2.5 to 5 inches of rain fell in the areas with the overnight rain. .
On Monday, the smothering heat broke temperature records, sent people to emergency rooms, buckled freeways, knocked out power and made a sweaty mess of those who dared to work or play in it. As if that wasn't bad enough, the hot air was also polluted, prompting state officials to issue a health advisory for the metro area.
Record-busting and near-record-busting temperatures will continue to bake the Upper Midwest and Northern Plains through the week, said Chris Franks, National Weather Service meteorologist in Chanhassen. The nationwide weather pattern has wreaked special havoc on the East Coast, where a violent storm four days ago knocked out power to tens of thousands of people now struggling with triple-digit heat.
Monday's high in the metro area hit 99, breaking the record for July 2 of 96, set in 1911. In St. Cloud, the high of 97 broke the 95-degree record set in 1921.
But it wasn't just the heat that made Monday so miserable. High humidity made it feel like it was over 100 degrees, Franks said.
As the mercury pushes toward 100 over the next few days, the humidity will make it feel even hotter.
With nighttime temperatures staying above 75, the National Weather Service issued an excessive heat warning because people without air conditioning will find no real relief as they try to fall asleep.
Compounding heat problems, a potential spike in ozone pollution had state officials issuing a health advisory on Monday and then again from noon to midnight on Tuesday. Ozone, known commonly as smog, acts almost like a "sunburn [for the lungs]," said Cassie McMahon, an air quality specialist for the Pollution Control Agency.
Pollutants released by vehicles, factories, household appliances, burning wood and paints and solvents chemically react with oxygen to create ozone in the air. On a hot, sunny day, that chemical reaction speeds up, generating more man-made ozone. Smoke wafting into Minnesota from wildfires out West also contributed to the problem.
The searing heat delivered a nasty mix of other problems. Pavement on Interstate 94 near Dowling Avenue N. and in West Lakeland Township buckled Monday evening. Small grass fires were reported as the once-green landscape withered after several days without rain. And scattered power failures plagued parts of the metro through the day.
In northern Minnesota, severe thunderstorms blew in Monday night, bringing large hail, rain and high winds that toppled trees, downed power lines and blew off metal roofs. In Bemidji, telephone lines were toppled and phone service was knocked out in most of the city. Authorities there asked residents to travel only in an emergency. An 80-mile-per-hour wind gust was reported near Grand Rapids, and gusts in excess of 60 mph were reported in Keewatin.
A break in the above-normal temperatures probably won't come until the weekend, when temperatures slip to the mid-80s on Saturday and low 80s on Sunday, Franks said. "We could be right around normal by mid-week next week," he said.
Until then, Minnesotans will have to sweat it out.
Heat stroke and fights
"The key is to stay hydrated," said Mary Woodley-Douglas, an emergency room nurse at Hennepin County Medical Center in Minneapolis. At least four people were treated Monday for heat-related illnesses at HCMC. And at least 10 people came into Regions Hospital in St. Paul because of heat-related and upper respiratory problems on Monday.
"We usually see a spike of these cases during these extended heat periods," said Regions spokeswoman Patricia Lund.
According to the National Weather Service, excessive heat claims more lives in the United States each year than floods, lightning, tornadoes and hurricanes combined.
For those who overheat, Woodley-Douglas recommends putting ice packs under the armpits and near the groin area or misting with cool water and turning on a fan to help the body cool as the water evaporates. And drink water and electrolytes, she said.
During heat waves, hospital emergency rooms also often see a spike in assaults, Woodley-Douglas said. "Why, I really don't know," she said. "It's neighbors fighting with neighbors. People hanging outside bars and then getting in fights. That sort of thing."
The heat might be behind the death of a 16-year-old girl who collapsed Sunday on a bike path in St. Michael, in the northwest metro, although the precise cause of her death will have to be determined by the medical examiner. The Wright County Sheriff's Office received an emergency call about 9:30 a.m. when Michaela Marie Olson, of St. Michael, collapsed. She died after being rushed to New River Medical Center in Monticello.
Maybe less running
The unrelenting heat through the July 4th week has some major Twin Cities events rethinking their game plans. The third annual Red, White and Boom Half Marathon in Minneapolis will be shortened from 13.1 miles to 5 miles, said Virginia Brophy Achman, executive director of Twin Cities in Motion.
More than 2,500 people are expected to toe the starting line. Organizers not only want to keep people safe, they also don't want heat-related injuries to overtax the emergency medical system from tending to others in the metro who might need of those services.
"It's just a lot harder to run when it's this hot," Brophy Achman said.
The 10-kilometer part of the Firecracker Runs in Excelsior also might be shortened, said race director Rick Recker. "We might make it a 5K, or we might suggest everyone run the 2-mile race," he said. "We'll see what the weather looks like on [Tuesday] and on Wednesday.
"We could make it a 10K, but it might not be any fun," he said. "Standing still is bad enough."
Staff writers Paul Walsh and Daniela Hernandez contributed to this report.
Mary Lynn Smith • 612-673-4788