Exodus 10:19-21

19Then the Lord changed the wind to a very strong west wind. This wind lifted the locusts up and it blew them away into the Red Sea. Not one locust remained in all the country of Egypt.

20But the Lord caused Pharaoh's mind to become hard again. Pharaoh would not let the Israelites go.

21Then the Lord said to Moses, ‘Lift up your hand towards the sky. Then it will become dark over the whole country of Egypt. It will be so dark that people will be able to feel it.’