Burning Island Puzzle

Sam is stranded on an island covered in forest.

One day, when the wind is blowing from the west, lightning strikes the west end of the island and sets fire to the forest. The fire is very violent, burning everything in its path, and without intervention the fire will burn the whole island, killing Sam in the process.

There are cliffs around the island, so jumping off is not an option. There are no buckets or any other means to put out the fire either.

How can Sam survive the fire?