No relief as deadly heat wave expands east

Dangerous heat wave that has brought soaring temperatures to much of the United States will spread into the eastern portion of the country Wednesday, the National Weather Service warned.

Excessive heat watches, warnings and heat advisories were in effect in more than 30 states Wednesday morning, in what the weather service described as "a large portion of the central U.S. and Ohio River Valley, as well as portions of the mid-Atlantic and northeastern states. Temperatures will feel like 100 to 110 degrees or higher during the afternoon hours."

The large area of high pressure bringing on the heat is expected to expand eastward through the week, bringing temperatures near 100 "by Thursday across the mid-Atlantic and parts of the Southeast. Excessive heat is forecast to grip most of the eastern half of the country -- with the exception of the Northeast and southern Florida -- through at least the weekend," the weather service said.

The heat wave in recent days has brought heat index values -- which measure how hot it feels -- to as high as 131, the weather service said.

Heat indices on Tuesday reached 129 in Newton, Iowa; 121 in Taylorville, Illinois; 122 in Gwinner, North Dakota, and 123 in Hutchinson, Minnesota.

Xcel Energy, which serves 1.64 million customers in North Dakota, South Dakota, Wisconsin and Minnesota, broke a demand record on Monday with 9,504 megawatts of power used, said Tom Hoen, a company spokesman. The old record set in August 2010 was 9,100 megawatts.

Utility companies in Iowa also reported record usage and said they could top those records again on Tuesday.

In Omaha, Nebraska, flood control work along the overflowing Missouri River was halted due to the heat, as officials worried that filling sandbags was too strenuous.

In Illinois, the second-largest corn and soybean producing state, the heat and humidity were not yet damaging crops, according to University of Illinois agronomist Emerson Nafziger. But a lack of rain was cause for concern.

"Corn is holding on so far," Nafziger said. "We're starting to get a little worried right now from a water standpoint.