Temperatures unlikely to exceed -20C in parts of Canada, while a red weather warning has been issued for Sri Lanka

An area of low pressure moving along the US-Canada border has brought heavy snowfall to parts of western Canada at the weekend. A weather warning has been issued for the provinces of Alberta and Saskatchewan for 150-250mm (6-10in) of snow.

As the weather system moves, it is expected to bring further snow to eastern parts of the country early this week. Pressure building after the snowfall is expected trap cold air from the north, triggering severe frost.