A relentless heatwave continued to bake most of the United States on Friday, with numerous areas expected to see record-breaking temperatures and forecasters warning there would likely be little relief throughout the weekend for most areas.

The steamiest conditions on Friday were expected in parts of Ohio and Indiana, where heat indexes were likely to soar past 37.8C and remain there most of the day.

Excessive heat warnings and advisories have been issued across the north east, the mid-Atlantic and in some western states.

Idaho officials said two people in their 60s have died of heat-related causes — the state’s first heat-related deaths of the year. Health officials did not release additional information about the victims on Friday, including where they died.

Two children play under a water sprinkler at Broad Ripple Park in Indianapolis
Two children play under a water sprinkler at Broad Ripple Park in Indianapolis (Darron Cummings/AP)

Millions of residents across the country have had their lives disrupted by days of unusually high temperatures.

In Michigan, utility crews from several states were working on Friday to restore power to thousands of suburban Detroit customers, two days after severe storms knocked out their power, leaving residents suffering amid the heatwave.

About 12,000 homes and businesses remained without power on Friday afternoon in Oakland County, a suburban area north of Detroit hit hard by Wednesday night’s storms that cut power to about 75,000 homes and businesses at its peak, said Brian Calka, DTE Energy’s vice president of distribution operations.

Between 500 and 600 crew members from utilities in Ohio, Indiana and Illinois were working with about 1,000 DTE Energy utility workers and another 1,000 tree-trimming contractors to get the power back on amid the heat. Mr Calka said the utility’s goal is to get the power back on for all its customers by late Friday or early Saturday.

“They are working in very, very tough conditions,” he said.

The US last year experienced the most heatwaves since 1936, experts said. An Associated Press analysis of Centres for Disease Control and Prevention data found that the excessive heat contributed to more than 2,300 US deaths, the highest number in 45 years of records.

The excessive heat was not the only weather-related issue in some states.

Several small towns in northern Minnesota continued to be inundated by floodwaters after a deluge of rain earlier this week, prompting the closure of major roads and leaving a costly trail of damage.

On Friday, Minnesota governor Tim Walz travelled to St Louis County, where people in one town paddled through flood-ridden streets in small boats and officials estimated the floods had caused at least 50 million dollars (£40 million) in damage and prompted the closure of more than 40 roads.

Several South Dakota campers who had gathered to see a now-cancelled race at Huset’s Speedway near Sioux Falls were rescued by boat on Friday.