The years after 1929 were disastrous for many American people. What was the 'Dust Bowl'?

One mark for each relevant point.
Responses may include the following:
- It affected the Plains in the early 1930s.
- The topsoil was blown away by heavy winds leaving the land unfit for growing anything.
- Drought had turned the land into dust.
- Overcultivation of wheat was a cause of the problem.
- Thousands of farming families were ruined and had to leave.