It comes in waves, like you've always heard, crashing and receding and pounding out of your control. Sit on the edge of the water on the beach and see if the waves stop lapping and splashing at your feet. They don't. Ever.
But grief is also like water in that sometimes you move past it, you go on with life and you think you're okay until you realize that your mascara is running down your face and the book you're holding is drenched. Then you notice the ultra fine mist that is falling on you. It's the slightest twinge of pain, now that you've noticed it, constant but undemanding.
Grief is like a shallow pool, deceptively calm, with jagged rocks just below the surface. Step in just the wrong way, at the wrong speed or without proper protection and you'll find yourself nursing an open wound again. Under some circumstances, it's possible to drown in a few inches of water.
Grief is the deep sea, without a floor or anything solid within reach, pressure mounting on all sides without the luxury of a moment to examine, consider, take a breath. It stretches out as far as the eye can see, sounds of an ear-bursting roar and fills the nose when all you want to do is breath in air. It overwhelms you when you're in it, but to those on the safety of land or in a boat, the danger seems minimal.
Grief, like water, can cleanse, it can purge, or a person can drown in it.