The churning snow dropped back to the ground again, and the fog slowly grew still.

There wasn't much to be seen for the fog grew denser by the second.

Where the path joined a dirt road, the fog grew more intense.

As if in response, the fog grew thinner before her eyes.

As they walked, the fog again grew thick around them.

The fog grew bright, as if a light were blooming in it.

The fog grew steadily thicker as a light rain began to fall.

The fog grew lighter as he went, but no less dense.

The fog grew thicker as the night stretched into the last dead hours before morning.

Also, the fog had grown so dense that it was impossible to see very far ahead.