Swarm of locusts

Interesting article from The Writer's Almanac

It was on this day in 1875 that the largest recorded swarm  of locusts in American history descended upon the Great   Plains. An estimated 3.5 trillion locusts made up the swarm.  It was about 1,800 miles long and 110 miles wide, ranging from Canada down to Texas.
Swarms would occur once every seven to 12 years, emerging  from river valleys in the Rocky Mountains and  sweeping east across much of the country. The size of the swarms tended to grow  when there was less rain, and in 1873, the American West began to go through  one of its driest periods on record.
The land was still relatively dry on this day in 1875 when  farmers just east of the Rocky Mountains began  to see a cloud approaching from the west. Some farmers noticed the distinctive  color of the cloud, glinting around the edges where the locust wings caught the  light of the sun.
People there that day said that the locusts descended like a  driving snow in winter, covering everything in their path. Some people  described the sound of the swarm landing as like thunder or a train. The  locusts blanketed the ground, nearly a foot deep. Trees bent over with the  weight of the insects, and large tree limbs broke off under the pressure.
They ate nearly every living piece of vegetation in their  path, as well as harnesses on horses, the bark of trees, curtains, and clothing  hung on laundry lines. They gnawed on fence posts and railings, and they  especially loved the handles of farm tools, which were left behind polished, as  if by fine sandpaper. Some farmers tried to scare away the locusts by running  into the swarm, and they had their clothes eaten right off their bodies.
In the wake of the swarm, settlers on half a million  square miles of the West faced starvation. Similar locust swarms occurred in  the following years, and farmers became desperate. But by the mid-1880s, the  rains had returned, and the swarms died down. Most scientists predicted that  the locusts would return with the next drought. Mysteriously, they did not.  Within a few decades they were believed to be extinct. For most of the 20th  century, no one knew what had happened to the locusts, but recent evidence  suggests that the cultivation of the land on the Great Plains changed the  geography so much so quickly that the Rocky Mountain  locust was unable to adapt. The last two live specimens of the Rocky Mountain  locust were collected in 1902, and those specimens are now stored at the  Smithsonian Institution.