WASHINGTON: Severe winter storms in the US have produced record amounts of snow.

With blizzard warnings being put in place for North Dakota, South Dakota, Nebraska, Wyoming, Minnesota, Iowa and Wisconsin, citizens are preparing for further heavy falls.

Storms have already dumped 14 inches of snow in Oklahoma City, which is 11.5 inches more than the previous record snowfall.

21 deaths have occurred on the roads since major storms hit a few days ago.

Hundreds of people have either been stranded or had to stop on highways due to the poor visibility conditions.

Some interstate roads are closed in North Dakota, Nebraska and Wyoming due to snow drifts and white-outs.

Flights have also been cancelled and some airports have been closed for at least two days.