Heavy snow in Britain forces Heathrow Airport to briefly shut a runway, cancel flights

A snow plough clears snow from Heathrow Airport, London Friday Jan. 18, 2013. Heathrow Airport briefly shut a runway and cancelled dozens of flights as a snowstorm caused widespread travel disruption across Britain. Heathrow’s northern runway re-opened Friday after being shut down briefly for de-icing and snow clearing. Some 180 flights were cancelled by midday. Rail traffic was disrupted and roads were forced to close amid plunging temperatures and icy conditions. (AP Photo/Steve Parsons/PA) UNITED KINGDOM OUT (The Associated Press)

A woman walks along a snowy path in Bristol, western England as snow shut roads and disrupted train travel Friday Jan. 18, 2013. Snow is expected to fall over a large part of Britain on Friday. (AP Photo/Ben Birchall/PA) UNITED KINGDOM OUT (The Associated Press)

A man looks at icicles at Gibson's Cave in Teesdale northeastern England Friday Jan. 18. 2013. Britain's could be hit heavy snow which is expected hit larger areas of Britain and travel companies have warned of widespread disruptions. (AP Photo/Owen Humphreys/PA) UNITED KINGDOM OUT (The Associated Press)

Heathrow Airport briefly shut a runway and canceled dozens of flights because of a snowstorm causing widespread travel disruption across Britain.

The London airport's northern runway was closed for 45 minutes and re-opened Friday after being de-iced and cleared of snow. About 180 flights were canceled by midday. Rail traffic was disrupted and roads were forced to close amid plunging temperatures and icy conditions.

Forecasts of inclement weather forced hundreds of schools to shut down.

Weather forecasters predicted around 12 inches (30 centimeters) of snow Friday in some areas. Forecasters say the worst of the snow was expected to the south and west of London, though most of the country would be affected.