Exodus 10:19-21

19And the Lord turned a very strong west wind, which took the locusts away and blew them into the Red Sea. There remained not one locust in all the territory of Egypt.

20But the Lord hardened Pharaoh’s heart, and he did not let the children of Israel go.

21Then the Lord said to Moses, “Stretch out your hand toward heaven, that there may be darkness over the land of Egypt, darkness which may even be felt.”