What was the worst sandstorm in history?

Black Sunday is widely considered to be one of the worst sandstorms in history. It occurred on April 14th, 1935 during the American Dust Bowl and displaced more than 300,000 tons of soil from the prairies of the plains states.

Black Sunday was the worst of hundreds of sandstorms that occurred during the Dust Bowl of the 1930s. All of the storms from this period are thought to have occurred from overfarming soil without replenishing the topsoil or replanting anchoring plants and grasses, leading the topsoil to become loose and sparse. The loose topsoil became a danger during windy spring months, causing massive destruction to homes and farms all over the area.