It happened, as they fled from before Israel, while they were at the descent of Beth Horon, that Yahweh cast down great stones from the sky on them to Azekah, and they died: they were more who died with the hailstones than they whom the children of Israel killed with the sword.
Note in Joshua 10:9-15 how the writer alternated references to the activities of the Israelites and God. He seems to have wanted to impress the reader with the fact than God and men were laboring together to secure the victory (cf. 1 Corinthians 3:9).