91 years ago today, on May 11, 1934 (March 28, 1934 in the lunar calendar), a black storm occurred in the United States. On May 11, 1934, a huge storm swept across the vast land of the eastern United States and western Canada. The storm blew from the most damaged dry areas of the western United States. The strong wind swept yellow dust, covering the sky and sweeping eastward, forming a huge moving dust belt 2400 kilometers long from east to west, 1500 kilometers wide from north to south, and 3.2 kilometers high. At that time, the sand content in the air reached 4O tons/cubic kilometer. The storm lasted for 3 days and swept over 2/3 of the land of the United States. More than 300 million tons of soil were blown away. Where the wind passed, wells and streams dried up, cattle and sheep died, and people were displaced from their homes. It was desolate. This is the "black storm" event that shocked the world. "Black storms", also known as sandstorms or sandstorms, have occurred in the United States several times, mainly due to the destruction of vegetation caused by land reclamation during the American pioneering period. This is a historic punishment of nature to human civilization. Due to the continuous reclamation of land resources by developers and the continuous deforestation of forests, the soil is seriously eroded by wind, and the continuous drought has exacerbated the phenomenon of land desertification. Under the action of high-altitude airflow, dust particles and sand are rolled up, and stocks of dust rise into the sky, forming a huge gray-black storm belt. The New York Times published a special report on the front page of the day.