This is a clear, level 9.2km-long trail (one way) that takes six hours return.
We must head into country that has no clear trail.
The normal eye could see nothing, but through the glasses a clear trail was left.
Their eyes were on the ground, following the clear trail.
She was a hunter now, following a clear trail of broken snow through the forest.
I couldn't break into them without making noise and leaving a clear trail.
They left a clear trail in the sky, and became known as tracers.
Nevertheless, there was sufficient snow for them to leave a clear trail.
"At least they've left us a clear trail to follow."
It had left a long and nebulous trail clear across the past.