Why is the hair of fierce Maenad used in the poem Ode to the West Wind?

Shelley in the poem Ode To The West Wind is describing a tumultuous scene in the stormy sky. Loose clouds are fleeing across the darkening sky driven by the force of the west wind. Angels of rain and lightning are flying everywhere. It is from this deep commotion that black rain and fire and hail has to burst out later. Poets have intenser emotions and imaginations than other human beings. If the lightnings spread there across that blue airy surge is a bright hair uplifted from the head of some fierce being, how big would be that head ? And how huge and horrid would be that body that produced such long, heavy, hoary and dazzling a hair as a lightning? A typical style of imagination of an unusually imaginative child! But poets are no older than children. A typical American child would think first of the Statue of Liberty. A British will normally think about the Rhodes islands. And Shelley thought about Maenad, the exhilarated woman attendant of Bacchus, the Greek god of wine, as such long a hair as the lightning could have come only from a woman. He may have seen the sculpture of Maenad in the Uffizi Gallery in Florence, Italy, when he visited there or might have heard about it from someone.