A rare snowstorm hit the United States. How is this weather formed?

A rare snowstorm hit the northeastern United States on the 26th, causing several states to declare a state of emergency and cancel the United Nations headquarters? International holocaust remembrance day? Related activities, etc. It has also had a great impact on people's lives. It is estimated that the snowfall will reach 50 to 70 cm, and the snowfall in some areas may even be as high as 90 cm. New york Mayor Bill de Blasio (Bill Bill de Blasio) said? This may be one of the biggest snowstorms in the history of New York City? . ?

I. Quality of life

Considering the warning of strong winds, snowstorms and floods, trees are likely to crush power lines, and the US authorities remind residents to prepare for power outages. The meteorological department also issued a flood warning. On the morning of 27th, the tidal water level in new york rose by nearly 1 m compared with previous years. More than 6,700 flights have been cancelled in the northeastern United States, and several major airlines have announced that they will allow passengers to cancel their flight reservations to new york and other places without any charge. In addition, most highways in the eastern United States are closed. Vehicles are prohibited on roads and streets, even take-away bicycles.

Two. cause

Snowstorms are mainly caused by the Great Lakes in the northern United States? Great Lakes Effect? When the cold air passes through the lake, it gets moisture and heat from the lake, forming a warm and humid airflow. Although snow is brought by the Atlantic Ocean instead of lakes, it is also called? Great Lakes Effect? Snowfall. When cold air strikes from the northwest, the Great Lakes effect will occur simultaneously in the five great lakes with superior geographical position. The Great Salt Lake in Utah, Hudson Bay in Canada and St. Lawrence Bay will all produce the Great Lakes effect snowstorm.

Three. The harm of long-term heavy snow

Although snow can protect crops from overwintering, if the snow is too thick, especially when winter has just arrived, some crops are still growing, and then the next heavy snow will often suffocate the crops and the crops will die. Too deep and heavy snow, long-term oppression of snow, coupled with poor ventilation and poor light transmittance inside snow, will cause mildew and leaf stem rot.