Sure. The ocean is full of waves. If one wave crashes on a cliff, there's a whole ocean of other waves lining up right behind it. So how does a crashing wave represent impermanence? Glad you asked.
Waves are kind of like snowflakes in that no two are identical. So, when that wave you're watching crashes on the cliffs, that's it. That wave is gone forever. Hope you didn't miss it.
Teasdale also makes a point of telling us that the waves are "blue" even though we all probably would have pictured them that way even if she hadn't. The result is a heightened sense of contrast when she describes the waves as "whitened" on the cliff.
Teasdale wants us to realize that things change from moment to moment—blue one second, white the next. If you don't take the time to appreciate things in the moment, you'll miss out. Thanks for the heads-up, Sara.