From The South Pole to The North Pole Adventurer, elite mountaineer and cross-country skier Kristin Harila recently suspended her solo and unsupported ski trek.

Frigid air that normally stays trapped in the Arctic has escaped, plunging deep into the United States for an extended visit that is expected to provoke teeth-chattering but not be record-shattering.

The plunging polar vortex is bringing subfreezing temperatures to some of the southernmost points of the U.S. A forming storm ...