Well, I disagree, with the interpretation of events known as Great Depression as a deflationary spiral.

Yes, there was a deflationary event. As there were many before, and the last one before in 1920-1921, when the wholesale prices fall by a whopping 40%. But a deflationary event does not make a deflationary spiral.

There were also a lot silly activism both from the part of the Hoover and Roosevelt. The later speaking, beside other things about outright nationalization, and driving thus the busyness investment into ground..

So a lot happened than which make the Great Depression Great but deflationary spiral is not THE explanation.