Kevin Martin of Corona, Calif., poses for a snapshot by an unofficial thermometer reading at Furnace Creek Visitor Center reading 128 degrees as a heat wave spreads across the American West on June 30, 2013 in Death Valley National Park, Calif. - 

We've been in the midst of a serious heat wave across much of the western U.S. the last few days. How hot? Even down in Phoenix, Ariz., where they're already braced for extreme summer heat, temperatures got far enough beyond extreme that US Airways had to cancel 18 flights. That’s just one example of how a few extra degrees can make a big difference on the nation's infrastructure and economy.

Let's start with those planes down in Phoenix. Todd Lehmacher, a US Airways spokesman and former pilot, says the airline had to cancel more than a dozen flights on regional jets because the temperature was off the charts. And he means that literally. The charts he’s speaking of are ones that calculate flight data, and on US Airway’s smaller planes, the charts only go up to 118 degrees. On Saturday, the airport reached 119 degrees.

“Since the charts don't go up that high,” Lehmacher says, “we couldn't accurately calculate, for instance, the runway distance required for take-off at that temperature.”

The hotter the air, the less dense it is, and that means the airplane’s wings have less lift and need more room to take off, he says.

If higher temperatures are the new normal, the airline could go to plane manufacturers and ask for more calculations to make the flight performance charts cover higher temperatures. But the costs of that would be significant. “That's something that we have to evaluate,” Lehmacher says. “We have to do a cost evaluation and see if that is something that we need.”

Over in the nuclear industry, some power plants have already made recalculations and adjustments. Since 1999, the Braidwood plant in Illinois has had to put in two requests with the Nuclear Regulatory Agency to increase the temperature limits on their cooling ponds. Krista Lopykinski is with Exelon, which operates the plant. She says the plant, which is almost 30 years old, first had to get permission from the NRC to use cooling pond water above 98 degrees. Then, last year, 100 degrees.

“In the report, it refers to meteorological conditions,” Lopykinski says of the NRC request. “Basically, the water was getting warmer.”

Then, there are our roads. When highways reach temperatures they weren’t designed to withstand, paving sections can expand and buckle. Tom Scullion*, an engineer at the Texas Transportation Institute says he’s seen sections get raised a foot into the air, like “a ski jump.”

Roads in any given region are designed to withstand the average of the 10 hottest days you can expect in a year. But Scullion says, that average might be changing. “If it’s an average over the last 50 years that might not be appropriate anymore.”

*CORRECTION: The original version of this story incorrectly identified engineer Tom Scullion. The text has been corrected.

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