AP Photo/The Herald-Palladium, Joe Rondone
The North Pier Outer Lighthouse in St. Joseph, Mich., is frozen over by cold winter weather Friday Jan. 25, 2013.
Even though much of the eastern and southern U.S. is experiencing much warmer than average weather this week, a wide swath of the country is still in the deep freeze, with wind chills in the teens and single digits across much of the Plains, the Southwest and the Northwest.
Frigid temperatures like these are sometimes used to refute the idea that the planet as a whole is getting warmer with each passing year. That's just not so, say NASA scientists, who point out that even on a warming planet, bitterly cold temperatures and harsh winter weather will still be possible and even commonplace.
One of the reasons they can coexist is a phenomenon known as Arctic Oscillation, a phrase used to describe the interaction of the jet stream and Arctic air during the winter. It can cause unseasonably cold air masses to sweep over what are normally temperate latitudes, NASA reports, making for unusually cold and severe winter weather across many parts of the U.S.
This bitterly cold air even can make it too cold to snow across regions of the country that normally see double-digit snowfall amounts each year, the Guardian newspaper of London reported last week. Because colder air has a lower capacity for holding water than warmer air, it can be more difficult for snow to form when temperatures reach the teens and single digits.
Six days of sub-freezing temperature at Puget Sound Energy's power plant in Goldendale, Wash. left a growing hoarfrost on anything exposed to the wind, including these headlights. (Photo credit: iWitnessWeather user gardnertoo)