As he grew older, Leonardo became increasingly aware that the forces of nature could sometimes go haywire. When it did, man and animals were powerless to defend themselves against the overwhelming destructive power of the elements.

He records tales of earthquakes swallowing seas and forests sinking down into the earth accompanied by torrential floods. Once he observed an enormous cloud over Milan “shaped like a huge mountain” which caused “a stupendous storm of wind”. He composed long and detailed descriptions of storms and compiled instructions regarding “the Deluge and its demonstration in painting.”

This drawing illustrates what happens when the “terrestrial machine” runs amok. In the upper drawing, the forces of nature hurl down raging winds that whip up stormy waters, causing them to crash onto the huge rocks below. In the lower drawing, huge trees are uprooted from the earth or snapped like twigs, as men and animals are dashed to the ground in the wake of a terrifying storm.

Leonardo’s representation of the invisible forces of nature is strikingly modern, both in terms of its graphic ingenuity and expressive power.

In Leoanrdo's words
I have seen motions of air so furious that they have gathered up and mingled in their course the largest trees of the forests and whole roofs of great palaces, and this same fury made a hollow opening with its vortex motion and excavated a gravel pit and transported the gravel, sand and water more than half a mile through the air.