Black Sunday is a term that was used to describe - O the Spindletop Gusher.
O the Dust Bowl.
O the Great Depression.
O the Galveston Hurricane of 1900.

The Dust Bowl

Explanation:

Black Sunday refers to a particularly severe dust storm that occurred on April 14, 1935 as part of the Dust Bowl in the United States. It was one of the worst dust storms in American history and it caused immense economic and agricultural damage.

these civilizations were located around fertile rivers, where they could produce an abundance of crops

“i think it is very plausible that if there are five votes to end the death penalty, it could be with the people who are on the court right now,” - smith

so basically it is not clearly and consistently imposed