Black Sunday was a very big storm that happened a really long time ago in the 1930s in the United States, mostly in the Great Plains area. It was a huge problem for the people who lived there because it caused a lot of dust to fly around and made everything very dark like night time.
The problem started because the farmers in the Great Plains were using all the grass and trees to make farmland, and they were also digging a lot of holes in the ground to find water. There was no grass or trees to hold the soil down, and when the wind came, it picked up all the dirt and made huge clouds of dust that covered everything.
People couldn't see anything, and they were choking on dirt that got into their mouths and noses. The dust was also getting into people's houses and ruining their furniture and making it hard to breathe.
The storm lasted for several years, and it caused a lot of problems for the people who lived in the area. Many families lost their farms and had to move away because they couldn't grow crops anymore. It was a very sad time for lots of people, and it taught us that we need to take care of the earth and not just use it all up without thinking about the consequences.