A huge winter storm has tightened its grip in the Southern areas of United States (US) leaving at least 21 dead and millions without power.

According to details, there has been a widespread power outage in Texas, where the energy grid was overwhelmed by a surge in demand.

Millions of people are experiencing immense difficulties to cope with the lack of power amid freezing temperatures.

Deaths have been reported in Louisiana, Kentucky, Texas, North Carolina and Missouri.

On the other hand, the met department of US has predicted that extreme weather conditions would continue until the weekend.

As per National Weather Service (NWS), although the worst of the storm has moved past Texas, but still millions of Americans are under an extreme weather warning.

More than 71% of the US is covered by snow.

The storm has also reached northern and central parts of Mexico, where millions of people have experienced days of intermittent power cuts.

The storm has disrupted air and road traffic across southern US, shuttering vaccination sites as well.