喜樂的心乃是良藥

這是一部長達 7 分半的影片，只有每年的 3 月和 4 月在美國加州的優勝美地國家公園

 才會看到令人讚嘆的自然現象~粉冰瀑布…引人入勝的危險森林，請慢慢欣賞。

Frazil ice looks like patches of snow, nestled among the trees.

But it's actually a Slushee-esque mixture of ice crystals that form in bitterly cold waters—

like the kind that run through Yosemite National Park in early spring.

Watching this video, you can see how frazil ice can appear to be just your average slushy creek water,

and, the next minute, turns into what looks like solid (if snowy) ground.

And then the ground moves.

If you're thinking that it's potentially dangerous, you'd be right.

In the video, park rangers talk about the risk of falling through frazil ice into frigid water

deeper than your head.