In pictures: US winter storm
- Published

A powerful Arctic winter storm has been sweeping across North America over the past few days bringing sub-zero temperatures, ice and snow blizzards and howling winds. The huge storm has affected around 70% of the US population and extends more than 2,000 miles from Texas in the South of the United States to Quebec in Eastern Canada.

The region around the city of Buffalo in the US state of New York has been one of the worst affected. Here, temperatures have been so low, that water spray from the waves of Lake Erie have instantly frozen into ice on this waterfront restaurant, causing icicles to form over the whole building.

Conditions are expected to remain difficult on Tuesday, with more than 20cm of snow expected to fall in parts of the state. Over the weekend around 250,000 homes and businesses experienced blackouts - although power has been steadily restored.

Temperatures across many central parts of America have plunged in recent days. The western US state of Montana was the worst hit by the cold, with temperatures dropping to a record breaking low of -45C. Here on the Yellowstone river in the state, the conditions caused mist to rise above the ice as the river froze.

In Canada, the most affected provinces have been Quebec and Ontario, with more snow expected on Tuesday. The extreme cold weather is due to a rare weather event called a "bomb cyclone", which is a fast-developing storm that happens when air pressure drops very quickly in a short amount of time.

The Arctic storm has also brought severe winds and ice and ploughs have been used to clear heavy snow, such as here in Denver in Colorado. Weather experts say that some areas saw temperatures drop by more than 20 degrees Celsius in just 30 minutes.

The weather has caused widespread travel disruption for millions of travellers. Freezing rain and icy conditions has meant that thousands of flights across America and Canada were cancelled, disrupting many people's Christmas travel plans.

Blizzards and icy winds have caused many problems on the roads too. In fact, conditions are so difficult that in order to keep residents safe, some parts of the country have banned people from driving.

The US National Weather Service has described the storm as a “once in a generation type event”. Weather forecasters say the storm will ease off in the next few days but the advice remains to avoid travelling unless essential.