Since February 2021, affected by the arctic air mass, the U.S. and Canada have experienced persistent low temperature, severe rain and snow, and extreme cold weather has occurred in many parts of the U.S. As of the 17^th Feb (Beijing time), the minimum temperature in the Great Plains of the U.S. was below 0℃. Among them, the minimum temperature in the northern U.S. and most of Canada was below -30℃, and the minimum temperature in parts of Midwestern Canada reached -35～-45℃. The minimum temperature of Mississippi, Texas and northern Mexico in the southern U.S. is below -5°C. During the past 10 days, the temperature in most of Canada, the northern part of the U.S. and the central and eastern parts of the U.S. was 8°C lower than normal. Figure below shows the observed temperature at Dallas, Texas of U.S. dropped significantly from 8^th Feb to 16^th Feb.

Moderate-to-heavy snow, local blizzard or heavy snow occurred in the mid-west of Canada and mid-east of the US; more than 70% of the U.S. area was covered by snow, which was the largest snow cover area since 2003, and the snow depth in some areas exceeded 50 cm with local area reaches about 2 meters. 

It is expected that in the next 10 days, cold air in North America will continue to be active, but the strength will be weakened, and the temperature will slowly increase. The average temperature in midwestern Canada and the western U.S. will be 1 to 3℃ lower than normal. There will be light to moderate snow or sleet in western Canada, northern and eastern U.S., and heavy snow in some areas.  （Editor: Xiang Xin/Huang Wei/Wang Yi）