Now the Symbol

Analayze

The hatched background shows a heavily rainy storm. The hurricane is clearly shown at the top-left corner which tends to reach the centre of the rectangle , so i hope it clearly shows the movement. And the spiral-flying fishes represent a school of fish chasing the clouds in the sky, as the warmer earth is evaporating the water faster.
This is the final Symbol representing tornado.

Here is how it's done.

1. This spiral cloud is created to be disorted to a hurricane shape later. Pen tool was used.

2. The next step is to disort the spiral cloud using the Roughen filter.

3. Now is time to twist the cloud to build a hurricane figure just by using Twirl filter.

4. To show the flying fishes over the clouds it is easy to draw one fish and copy ,resize and rotate to follow a spiral path using the pen tool. The stroke is to be changed to the marker tool found on the brush panel.

5. The final step is to create the rainy background. To do so, a rectangle with the navy-blue fill is needed. After that the hatch-effect filter is all need to be done.