The signs of global warming have now officially made the transition from "intellectually worrying" to "Book-of-Revelations-style creepy." According to MSNBC, new layers of colder-than-usual air at superhigh altitudes are taking normal jetstream -- trails of ice in the air left by airplanes -- and transforming them into plummeting bricks of ice the size and weight of anvils:

Ice clouds made from crystallized vapor trails of aircraft are well-known to pilots, but Martinez-Frias suggests that because global warming involves one level of the atmosphere getting colder while another gets hotter, some ice clouds now remain longer.

Their centers then fall through the atmosphere, bouncing and gathering mass, to end up smashing through a car windshield or, more usually, landing softly in a field, he suggested.

The first megacryometeor found this year in Spain — by a startled farmer riding his tractor in Soria — weighed 35.27 pounds (16 kilograms).