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In this task, you are given a context paragraph, a question based on that and corresponding answer of a question. Your task is to generate supporting fact/knowledge from context paragraph which helps in answering a given question.

The Dust Bowl, also known as the Dirty Thirties, was a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s; severe drought and a failure to apply dryland farming methods to prevent wind erosion (the Aeolian processes) caused the phenomenon. The drought came in three waves, 1934, 1936, and 19391940, but some regions of the high plains experienced drought conditions for as many as eight years. With insufficient understanding of the ecology of the plains, farmers had conducted extensive deep plowing of the virgin topsoil of the Great Plains during the previous decade; this had displaced the native, deep-rooted grasses that normally trapped soil and moisture even during periods of drought and high winds. The rapid mechanization of farm equipment, especially small gasoline tractors, and widespread use of the combine harvester contributed to farmers' decisions to convert arid grassland (much of which received no more than 10 inches (250 mm) of precipitation per year) to cultivated cropland. Question: Woody Wuthrie wrote the song "Do Re Mi" which was about migrants and their experiences when they arrive in California and are greeted with severe storms that came in waves in what years? Answer: 1934, 1936, and 19391940
Output:
The drought came in three waves, 1934, 1936, and 19391940, but some regions of the high plains experienced drought conditions for as many as eight years.