Millions of Americans sweated through yet another scorching day as temperatures soared Sunday across the U.S., while residents were rescued from floodwaters that forced evacuations across the Midwest, including in an Iowa town where the flood gauge was submerged. One person was killed during flooding in South Dakota, the governor said.
From the mid-Atlantic to Maine, across the Great Lakes region, and throughout the West to California, public officials cautioned residents about the dangers of excessive heat and humidity. In Oklahoma, the heat index โ what the temperature feels like to the human body โ was expected to reach 107 degrees (41 degrees Celsius) on Sunday.
In the Midwest where South Dakota, Iowa and Minnesota meet, floodwaters rose through the weekend. In northwest Iowa, 13 rivers flooded the area, said Eric Tigges of Clay County emergency management. Entire neighborhoods โ and at least one entire town โ were evacuated, and the town of Spencer imposed a curfew Sunday for the second night in a row after flooding that surpassed the record set in 1953.

โWhen the flood gauge is underwater, itโs really high,โ Tigges said in a news conference organized by Spencer officials.
Gov. Kim Reynolds declared a disaster for 21 counties in northern Iowa, including Sioux County. In drone video posted by the local sheriff, no streets were visible, just roofs and treetops poking above the water.
Reynolds told reporters Sunday that more than 1,000 displaced residents slept in shelters Saturday night. National Guard troops were helping with water rescues and transporting needed medications lost in flooding.
โBusinesses are shuttered. Main streets have been impacted,โ Reynolds said. โHospitals, nursing homes and other care facilities were evacuated. Cities are without power, and some are without drinkable water.โ

National Weather Service meteorologist Donna Dubberke said parts of northern Nebraska, southeastern South Dakota, southern Minnesota and northwest Iowa received eight times the typical average rainfall. And more heavy rain was expected this week.
In South Dakota, Gov. Kristi Noem declared an emergency after severe flooding in the southeastern part. Several highways were closed.
Areas south of Sioux Falls, the stateโs largest city, had an estimated 10 to 15 inches (25 to 38 centimeters) of rain over three days, National Weather Service hydrologist Kevin Low said.
At least one person died in the floods, Noem said Sunday, without providing details.

Several rivers, including the Big Sioux, James and Vermillion, were expected to peak sometime Monday through Wednesday night, the governor said at a news conference.
โI want to remind everybody to remember the power of water and the flow of water, and to stay away from flooded areas,โ Noem said. โWeโve got a few days in front of us here thatโll be a little rough, but weโll get through it."
Emergency management officials in the small South Dakota community of Dakota Dunes on Sunday issued a voluntary evacuation order for the areaโs roughly 4,000 residents. Dakota Dunes is near the Nebraska and Iowa borders and is sandwiched between the Missouri and Big Sioux rivers, both of which are expected to crest in the coming days. Emergency management in Dakota Dunes warned residents that a mandatory evacuation could come quickly if flood barriers are breached.
Little rainfall was forecast in coming days as high water continues working its way down the Missouri River, cresting at Sioux City, Iowa, overnight Sunday, at Omaha, Nebraska, on Wednesday, and at Nebraska City on Thursday, Low said.

Minor to moderate flooding was expected along the Missouri River, according to officials with the U.S. Army Corps of Engineers.
โAs long as the levees hold, weโre not expecting any major impacts,โ said John Remus, water management division chief for the corps in the Missouri River basin.
But elsewhere, the heat was the biggest worry.
โItโs more important for people who are going to be outside to stay hydrated, because heat, humidity and low winds, even if youโre in good shape and not really acclimated to it, it could be a danger, โ said Bruce Thoren, a National Weather Service meteorologist in Oklahoma. โIt happens quickly.โ

The cities of Washington, D.C., Baltimore and Philadelphia all saw record heat on Saturday, with more high temperatures expected again Sunday.
Lamont Cousins, who owns the Ampersea restaurant on Baltimoreโs waterfront, said business had been slow this weekend. The 40 outdoor dining seats at the restaurant, usually packed this time of year, were empty until around dinnertime Saturday.
โI think itโs affected us because people are staying home scared,โ he said.
On Saturday, when he went to put umbrellas on the tables, it was already over 90 degrees. But Cousins said heโs not too worried about the lost business โ and he expected Sunday would be better.

โYesterday, it was nobody walking around. Itโs hotter today, but thereโs a breeze going. Yesterday, it just felt like I was being punished,โ Cousins said.
Last year the U.S. experienced the most heat waves since 1936, experts said. An AP analysis of data from the Centers for Disease Control and Prevention found that excessive heat contributed to more than 2,300 deaths, the highest in 45 years of records.
The National Weather Service warned of the potential for rare tornadoes in the Northeast later Sunday. Tornadoes on Saturday struck in Wisconsin, leveling the historic Apple Grove Lutheran Church, founded in 1893 in the town of Argyle.
โThe good news is we are all safe,โ Dan Bohlman, pastor of Apple Grove Lutheran Church, said on the church website.

Marvin Boyd, meteorologist at the National Weather Service in Burlington, Vermont, said a severe thunderstorm warning was issued for parts of northern New York as a storm with wind gusts exceeding 60 mph (95 kph) and the threat of tornadoes head toward Vermont near Lake Champlain. It is one of several expected to pass through the region Sunday afternoon.
โItโs an unusual alignment of ingredients for Vermont and northern New York to produce a threat of tornadoes,โ Boyd said.
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Associated Press journalists Summer Ballentine in Columbia, Missouri; Leah Willingham in Charleston, West Virginia; Julie Walker in New York; Ron Todt in Philadelphia; and Michael Casey in Boston contributed reporting.