"And the Israelites came into the sea on dry land, the waters a wall to them on their right and on their left. And the Egyptians pursued and came after them, all Pharaoh’s horses, his chariots, and his riders, into the sea. And it happened in the morning watch that the LORD looked out over the camp of Egypt in a pillar of fire and cloud and He panicked the camp of Egypt. And He took off the wheels of their chariots and drove them heavily, and Egypt said, “Let me flee before Israel, for the LORD does battle for them against Egypt.”
Robert Alter: "in the morning watch": By Israelite reckoning, the last third of the night, from 2:00 a.m. to 6:00 a.m. The Hebrews, then, would have marched through the Sea of Reeds during the night, literally plunging into the dark, for the pillar of fire would have been behind them rather than leading them on their way. "the LORD looked out": The Hebrew verb hishqif is generally reserved for looking down or out from a high vantage point.
"in a pillar of fire and cloud": The double identification is presumably because of the moment of transition toward daybreak when the fire becomes cloud. The narrative sequence at this point is not entirely clear, but it might be sorted out as follows: during the night, the Israelites make their way across the sea, with the protective pillar of fire following after them. The Egyptians, seeing their movement, which would be joined with the receding pillar of fire, begin pursuit. As day breaks, G-d looks down on them from the pillar of fire just as it turns back into a pillar of cloud.