Three-fourths of the United States are under the influence of the cold air wave called the polar vortex. Authorities continue warning citizens against the dangers of freezing temperatures.

The number of people who died due to cold weather and snow rose to 21. In addition to school and government offices due to extreme cold, many businesses are also closed.

Arctic temperatures continue to affect the freezing days of the last 25 years in the United States. Many flights are canceled due to cold and icing, while waterfalls, lakes and a lot of things are frozen.

The National Meteorological Service announced that air temperatures will rise over the weekend.

ILKHA