What does "in fingers of spray" mean?

I am reading the book Lord of the Flies and I don't understand the phrase below:

Now the sea would suck down, making cascades and waterfalls ofretreating water, would sink past the rocks and plaster down the seaweed like shining hair: then, pausing, gather and rise with a roar, irresistibly swelling over point and outcrop, climbing the little cliff, sending at last an arm of surf up a gully to end a yard or so from him in fingers of spray.

If you look at https://www.sciencephoto.com/media/968537/view/wave-breaking-over-rocks-in-stormy-weather you will see seawater spray being forced into the air by the breaking of waves in rocky and constricted places. The energy stored in the waves is converted into turbulence, into disorganised jets and splashes that shoot upwards, sometimes with great speed and force. These ejections of drops and mist may look like ghostly fingers reaching upwards. Hence the term fingers of spray.