plow

Snow plows clear downtown lanes on Interstate 75/85 during a winter storm on Wednesday, Feb. 12, 2014, in Atlanta.  Across the South, winter-weary residents woke up Wednesday to a region encased in ice, snow and freezing rain, with forecasters warning that the worst of the potentially "catastrophic" storm is yet to come.

David Tulis/AP

A snow plow clears downtown lanes on Interstate 75/85 during a winter storm on Wednesday in Atlanta.

People make their way on plowed paths in the frigid temperatures outside city hall in Toronto on Monday, Jan. 20, 2014.

Nathan Denette/The Canadian Press/AP

People make their way on plowed paths in the frigid temperatures outside city hall in TorontoRead more

Backdropped by Popocatepetl Volcano, Mexico's second highest peak just 55 km southeast of Mexico City, a farner plows the land in San Nicolas de los Ranchos, in the state of Puebla, on May 14, 2013. The National Disaster Prevention Centre (CENAPRED) raised the alert level on Sunday to "yellow phase three" as the Popocatepetl continues to spew ash and smoke.

Ronaldo Schemidt/AFP

A farmer ploughs the land in San Nicolas de los Ranchos, in the state of Puebla, with the Popocatepetl volcano, Mexico’s second-highest peak, 55km southeast of Mexico City, in the background. The National Disaster Prevention Centre raised the alert level to ‘yellow phase three’, as the Popocatepetl continues to spew ash and smoke.