ST. PAUL, Minn. – As heat across a big chunk of the U.S. drives people into pools and lakes to cool off, public health officials are worried about a heightened risk of drowning.

Minnesota has had more drowning deaths so far this year than any time in the past decade, and officials in Illinois and Michigan are seeing an uptick in some areas, too. Drowning deaths historically go up in the summer months, but the intensely hot weather may also be putting even more people at risk as they flock to water for relief, some without swimming skills.

“When you’ve got more people out there, the chances of someone getting hurt or killed are increased just by the fact you’ve got numbers on the water,” said Kim Elverum, spokesman for the Minnesota Department of Natural Resources.

Much of the central and eastern U.S. has experienced particularly hot weather in recent days, with temperatures climbing into the 100s in several cities. In the Midwest, low temperatures have been setting record highs, so people aren’t able to get relief even overnight.

Excessive-heat warnings were in place Friday for all of Iowa, Indiana and Illinois as well as much of Wisconsin, Michigan, Missouri, Ohio and Kentucky, and parts of Pennsylvania, Maryland, New Jersey and Delaware. The National Weather Service said it expected heat warnings and advisories to be continued or expanded today, with the heat largely centered over Ohio Valley and Mid-Atlantic states.

“I hate it,” Brenda Jones, 55, said Friday as she sat on a covered porch outside her Detroit apartment building in a tank top and shorts. “When the sun hits the porch at 5 p.m., I run in and take cover. Give me fall.”

Few states release hard numbers on drownings at this point in the year, but Minnesota counted 25 non-boating drowning deaths through July 5, the highest in a decade. The deaths happened in lakes, rivers and ponds as well as man-made pools, hot tubs and bathtubs. The numbers include four who fell through ice in the winter.

Even without the drownings, the heat has resulted in deaths. An Ohio coroner blamed excessive temperatures for the deaths of three people found alone in their homes earlier this week, and St. Louis officials have reported three heat-related deaths in recent days.

In Rock County, Wis., a coroner said the death of an 83-year-old woman was definitely due to the heat.

And in Tennessee, authorities have opened a criminal investigation into last week’s heat deaths of two young brothers.

Storms that have knocked out power in some states have made riding out the heat even more difficult.

Some 200,000 people were without power Friday in West Virginia, and heat advisories were in place through today for part of that state.