The polar ice cap covered about 5.23 million square miles last month -- 19,300 square miles smaller than the previous minimum record set in January 2006 and about 490,000 square miles below the 1979-2000 average, according to a new analysis by the National Snow and Ice Data Center.

To put those figures in perspective, it's as though a frozen habitat about as large as California, Oregon, Washington and Nevada combined had turned to slush.

While the extent of frozen ocean near Alaska was above normal, coverage off eastern Canada was meager, especially in Hudson Bay, Hudson Strait and Davis Strait.

"Normally, these areas freeze over by late November, but this year Hudson Bay did not completely freeze over until mid-January," the NSIDC reported. "The Labrador Sea remains largely ice-free."

December ice coverage was also the lowest on record for that month. Scientists blame both records on a climate pattern called the Arctic Oscillation.

"Air temperatures over much of the Arctic were (4 to 11 degrees Fahrenheit) above normal in January," the NSIDC said.

"As in December 2010, the warm temperatures in January came from two sources: unfrozen areas of the ocean continued to release heat to the atmosphere, and the wind patterns (that) brought warm air into the Arctic."