When:

* Anytime there is rain: Rain can dislodge soil particles and carry them away, especially when it's heavy or intense.

* During periods of strong wind: Wind can pick up and carry soil particles, especially in dry or arid areas.

* After disturbances: Activities like deforestation, construction, and agriculture can expose soil to erosion.

* When soil is dry and unprotected: Dry soil is more susceptible to wind and water erosion.

Where:

* Sloping land: Gravity plays a major role in soil erosion, so slopes are particularly vulnerable.

* Areas with sparse vegetation: Plants help hold soil in place with their roots.

* Agricultural fields: Tilling and leaving fields bare can lead to soil erosion.

* Construction sites: Exposed soil is highly susceptible to erosion until it's stabilized.

* Riverbanks and coastlines: Water action from rivers and oceans can erode soil rapidly.

* Deserts: Wind erosion is a significant factor in deserts, carrying away sand and other soil particles.

Specific Examples:

* Dust Bowl: A severe drought and poor farming practices led to widespread soil erosion in the Great Plains of the United States during the 1930s.

* Amazon Rainforest: Deforestation and agricultural practices have led to significant soil erosion in the Amazon basin.

* Coastal regions: Rising sea levels and storm surges can cause significant erosion along coastlines.

It's important to understand that soil erosion is a natural process, but human activities can significantly exacerbate it.