An Ekman spiral is another version of this spiral pattern created by disturbance. Ekman spirals are created in the ocean in response to steady wind. They move at right angles to the wind because they are influenced by the turn of the earth (spirals move to the left in the Southern hemisphere).
Ekman spirals are found in wind patterns as well - surface winds blow at an angle to winds at altitude in the Northern hemisphere.
Ekman spirals and other patterns of turbulence can be created by the tops of trees in a forest, thus sending dust into the air that rain can form around. Trees thus create rain (this is just one aspect that trees contribute to rainmaking).
When trees are clear cut on the side of a mountain near the sea, where moisture is gathered and sent inland, the moisture can continue onward and dissipate rather than being slowed, concentrated and made heavy via particulates so that it rains. Large forests make rain.
The taiga in the NW of this country can cause rain hundreds of miles inland. The redwood forests used to do more of this before 2 million acres were cut down. They still create rain, and wind patterns at treetop level contribute to this process (there are a number of ways that trees contribute to making rain which we’ll get into later