Eighteen words with three sentences but with too many incomprehensibles

The passage below is from Fathoms: The World in the Whale Hardcover by Rebecca Giggs.

A group of us slept lightly in the dunes, arrayed like question-marks and commas on the white sand. Our minds cast to the cetacean huffing beyond the swale, then swooped into softer visions. The sounds of surfers arriving in the dark woke me. I brushed a pearly skin of sand off my cheek, my shoulder, one thigh. Were those sharks, raiding a lux channel tipped up by the moon? Hard to tell. We resolved that the whale had been washed too high on the beach for any shark to reach it. Every detail, peculiar and particular, rinsed by pewter light. Ridges in the sand. Plants like handfuls of knives. It felt cold to us.

Here I am a volunteer who wants to help save a stranded whale. I took a light sleep on the sand and woke to the sounds of surfers. Still not completely woken, worrying about the whale, I mistook surfers for sharks to kill it. But not possible.

Here’s my questions.

Every detail, peculiar and particular, rinsed by pewter light.

This sentence seems to mean I still cannot see things clearly because of pewter light, that is moonlight.

Am I right?

Ridges in the sand.

This doesn’t make any sense to me?

Can you give me a glimpse of it?

Plants like handfuls of knives.

This one is the most mysterious of all.

I cannot even decide whether it means plants love handfuls of knives or it means plants look like handfuls of knives.

And I don’t even understand why plants have anything to do with handfuls of knives.

Can you tell me any sense of it?

Thanks in advance.