N America weather: Polar vortex brings record temperatures

Parts of the US are braced for potentially record-breaking low temperatures as a "polar vortex" brings more freezing weather.

A winter storm has already blanketed areas of Canada and the north-eastern US with up to 2ft (60 cm) of snow.

It has been blamed for 16 deaths and the cancellation of more than 5,000 flights since Wednesday.

A plane from Toronto has slid into snow as it turned onto a taxiway after landing at New York's JFK airport.

No-one was hurt in the incident but all flights at the airport were suspended for two hours because of icy runways.

The plunging temperatures result from the polar vortex, a counter-clockwise-rotating pool of cold, dense air.

Forecasters say temperatures in the US Mid-West could feel as low as -58F (-50C) with the effect of wind chill.

Authorities have warned residents to remain indoors, both for their own safety and to keep roads clear for snow removal.

In Canada, tens of thousands of people on the island of Newfoundland remain without power due to a transformer fire linked to heavy snow.

- BBC.co.uk