The sharp division is a result of the behavior of the polar jet stream, the fast-flowing current of air that moves west to east across the northern hemisphere, and which can serve as a barrier separating weather patterns. Recently the jet stream has been sitting far north above the western half of North America, which allows warm air from the Pacific Ocean to move over the western states before dipping south over the eastern states. On the eastern side of the continent, however, the cold air is being held in place by the so-called bomb-cyclone in the Atlantic.

This meteorological divide has already been with us for a few weeks. More than 700 records for daily low temperatures have been recorded across the midwest and northeast since Dec. 24, while more than 600 record highs have been set in western states, according to the Washington Post.

The weather patterns have also given rise to weird anomalies. On Jan. 2, for example, the temperature was warmer in Anchorage, Alaska (high of 48°F) than New Orleans, Louisiana (high of 39°F).

Meanwhile, further north, the Atlantic coast was pounded by a freakish combination of strong winds and bone-chilling cold. In Boston, high tides flooded streets before the temperature plummeted further, freezing cars in place:

Fortunately for Boston drivers and iguanas, the weather is expected to return to more normal conditions next week.

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