Fog closes Chicago beaches as city bakes

CHICAGO, July 19 (UPI) -- A brutal heat wave held its grip on much of the U.S. midsection Tuesday and headed for the East Coast, meteorologists said.

To add to the misery in Chicago, swimming was banned at all city beaches because of thick fog that prevented lifeguards from spotting swimmers in trouble, the Chicago Tribune reported. Lifeguards were told they could end the ban at individual beaches as conditions improved.

David Beachler of the National Weather Service said the fog was caused by hot winds blowing over the comparatively cool waters of Lake Michigan: "It's kind of like if you were to open up the freezer door in your refrigerator and you have this cloud of water vapor that comes out of it," he said.

At least 14 states recorded 100 degrees Monday and more than 40 topped 90 degrees, AccuWeather.com said. And heat indexes felt like 120 degrees in many places across the Plains and Midwest.

"The thing about this heat wave is you have the heat ... you have the humidity ... and you have no wind," said meteorologist Bernie Rayno.

By the end of the week, temperatures in the Northeast will reach 100 degrees and feel hotter, AccuWeather predicted. But a cold front moving into the northern Plains should give Montana, the Dakotas and Minnesota a bit of relief.

Temperature records were tied or broken Monday across the Midwest, including Ankeny, Iowa, where the mercury hit 102 degrees, the National Weather Service said.

Jacob Beitlich, a weather service meteorologist in Des Moines, told CNN this heat wave is especially dangerous because humidity is high and temperatures are not falling enough at night to let people cool off.

In Kansas City, Mo., medical examiners are investigating a 10th suspected death from extreme heat, a woman in her 50s, The Kansas City Star reported.