July 21, 2011 -- The extreme heat system scorching the nation is on the move eastward toward major cities today as it impacts airports, tourist spots and emergency rooms.
At New York's Statue of Liberty, officials closed the statue's crown area as temperatures inside reached 110 degrees this afternoon.
Meanwhile, emergency rooms say they are "stacked up" with patients as the heat dome that has scorched the Southwest and Midwest.
"We're up in overall cases by 10 percent every day this week," the Detroit Medical Center reported to ABC News today. "The chief of emergency medicine estimated that 15 percent to 20 percent are heat exhaustion or heat-related cases."
The center said that one man with diabetes was found unconscious on the floor of his non-air-conditioned home.
"He's still not out of the woods," the center said.
There are 141 million people in more than two dozen states under heat advisories.
As many as 22 people have died because of the extreme heat and humidity, the National Weather Service reported Wednesday -- and there is no immediate end to the scorching temperatures in sight.
Heat indexes from 105 to 115 degrees were expected from the Midwest to the East Coast Thursday.
Across the Midwest, people were being treated in hospitals for illnesses related to the heat. In Wichita, Kan., hospitals saw 25 heat-related illnesses, while in Des Moines, Iowa, they saw 16.
According to hospital officials, a person can die within half an hour once they get heat exhaustion.
Officials warned people to watch for signs of heat exhaustion. In these conditions, the body, even at rest, can lose a quart of fluid an hour.
"You stop sweating I believe around 103-104, and so you start, at that point, the body is really starting to shut down," said Dr. Jordan Moskoff from John Stroger Hospital in Chicago.
"Excessive heat watches and warnings and heat advisories are in effect for a large, contiguous area of the central United States. Above-normal temperatures are expected to last the next couple of weeks over much of the eastern half of the United States," the National Weather Service said.
Since July 13, the heat dome -- a shroud of high pressure that is trapping and compressing hot, humid air from the Gulf of Mexico -- has brought 100-degree temperatures to more than half of the country.
Chicago reached almost 100 degrees on Wednesday, making it the hottest temperature in the Windy City in six years, with a heat index of 112 in parts of the city. One of the highest heat index readings from Wednesday was in Indiana, where it felt like 120 degrees.
With little rain this season, crops are struggling in the Midwest.
In the Quad Cities area straddling Iowa and Illinois, the heat and humidity were stressing the crops, especially corn, ABC News' Terry Swails reported. Farmers were very concerned it was going to cut into yields.
In Indiana, farmers in the central part of the state were trying to cope with the scorching sun.
"It's hard on the plants that are fairly young," said Carol Waterman of Waterman Farms, which grows produce in Indianapolis. "If this continues, the plants that are setting blossoms will abort those blossoms because when they are under stress. The first thing they give up is that fruit."
Air travel is experiencing complications, too, as those hoping to travel with their pets may be shut out. At Chicago's O'Hare Airport, pets were banned from flying in cargo holds of planes because of the extreme heat danger, ABC News' Barbara Pinto reported.
Ways to Beat the Heat
The National Weather Service has safety tips for adults looking to keep cool.
Slow down. Try to reduce or cancel any strenuous activities, or reschedule them for the coolest part of the day.
Wear lightweight, light-colored clothing to reflect sunlight and heat.
Eat lighter foods. Meat and other proteins increase metabolic heat production and could cause even more water loss.
Drink plenty of water, but avoid alcohol and caffeinated drinks.
Spend more time in air-conditioned places. If you don't have an air-conditioner in your home, go to a library, store or other location for part of the day to stay cool.
Avoid getting too much sun. Sunburn can reduce your body's ability to release heat.
The Associated Press and ABC News Indiana affiliate WRTV-TV and Chicago affiliate WLS-TV contributed to this story.