cold snap

US freezes in record-breaking cold snap

In parts of the US and Canada, temperatures were forecast to fall below -29 degrees Celsius, with wind chill making it feel more like -67° on Friday night.

In Canada, high winds have knocked out power for tens of thousands of residents in Nova Scotia.

Thousands of snow ploughs are clearing roads across the US East Coast.

The extreme weather has so far been linked to up to 19 deaths in the US and two more in Canada, according to reports.

You're more likely to catch flu after a cold snap, study says

Now, a new study published in the Journal of Clinical Virology is shedding some light on exactly how cold weather and the spread of viruses are linked.

It turns out, seasonal flu outbreaks first appear each year about a week after the winter's first cold spell -- or at least that's what happened in Sweden, over the course of three years when researchers tracked weather patterns and the prevalence of the virus.