Even if I accept a natural explanation concerning these events, that they occurred in this precise geographic location and that they occurred at this precise moment in time gives me reason enough to conclude they were miracles from God.

It is true that most people are under the impression that Moses lifted his rod and the sea immediately divided and see this as a virtually unparallel supernatural miracle. A careful reading of the text gives some credibility to your interpretation that God intended this even to appear more natural than supernatural since the splitting of the sea did not occur instantaneously but over the course of an entire night (Exodus 14:21).

The more immediate miracle is that God placed a pillar of fire and cloud (or a volcano) between the Israelite and Egyptian camps, making it impossible for Pharaoh’s troops to advance against the Hebrews. While the Egyptians were held in check by this pillar and cloud, God causes an enormous east wind to divide the sea in half by forcing the waters to both sides.

Eventually, this enables the Israelites to cross over the dry land in the middle. Because God made the sea’s splitting occur in a seemingly natural manner, Pharaoh and his troops, who are obsessed with the overtaking of the runaway slaves, fail to perceive the miracle occurring before their eyes.

Years later the inability of someone who is obsessed to see the hand of God is similarly reflected in the tale of Balaam, who is too furious at his disobedient donkey to wonder at the peculiarity of the animal’s talking (see Numbers 22:28-35). And millenniums later we have liberal theologians who are unable to see the hand of God in miracles, either those that are supernatural or those that may be natural in occurrence but are unexplainable as to why they occur at such a time and place.

The Egyptians followed the Israelites into the sea, but as soon as the Israelites finish crossing God instructs Moses to extend his hands over the water. He does so and the waters quickly rush back in and Pharaoh and all his troops drown. Only when the Israelites see their oppressors dead do they finally express faith in God and believe his servant Moses.

Thus you see their faith, often like our faith, lasts only until the next crisis occurs.