Exodus 10:19-21

19and the Lord turned a very strong west wind, and it picked up the locusts and blew them into the Red Sea. Not one locust remained in all the territory of Egypt.

20But the Lord hardened Pharaoh’s heart, and he did not release the Israelites.

21The Lord said to Moses, “Extend your hand toward heaven so that there may be darkness over the land of Egypt, a darkness so thick it can be felt.”