"The naked child ran out of the hide-covered lean-to toward the rocky beach at the bend in the small river. It didn't occur to her to look back. Nothing in her experience ever gave her reason to doubt the shelter and those within it would be there when she returned.
She splashed into the river and felt rocks and sand shift under her feet as the shore fell off sharply. She dived into the cold water and came up sputtering, then reached out with sure strokes for the steep opposite bank. She had learned to swim before she learned to walk and, at five, was at ease in the water. Swimming was often the only way a river could be crossed.
The girl played for a while, swimming back and forth, then let the current float her downstream. Where the river widened and bubbled over rocks, she stood up and waded to shore, then walked back to the beach and began sorting pebbles. She had just put a stone on top of a pile of especially pretty ones when the earth began to tremble."
If you really want to learn to write descriptively, every once in awhile you have to step back and learn from a master.