US braces for snow storms as 'polar vortex' blankets Midwest

Temperatures in the US are expected to plummet to record lows after a weekend of heavy snowfall across much of the Midwest.

The plunging temperatures result from the polar vortex, an anti-clockwise pool of cold, dense air.

Hazardous conditions in many states have led to cancelled flights and motorists are being warned against venturing out onto the roads.

Mike Wooldridge reports.