Exodus 14:21 Moses stretched out his hand toward the sea, and the LORD drove the sea apart by a strong east wind all that night, and he made the sea into dry land, and the water was divided. 14:22 So the Israelites went through the middle of the sea on dry ground, the water forming a wall for them on their right and on their left…14:26 The LORD said to Moses, “Extend your hand toward the sea, so that the waters may flow back on the Egyptians, on their chariots, and on their horsemen!” 14:27 So Moses extended his hand toward the sea, and the sea returned to its normal state when the sun began to rise. Now the Egyptians were fleeing before it, but the LORD overthrew the Egyptians in the middle of the sea. 14:28 The water returned and covered the chariots and the horsemen and all the army of Pharaoh that was coming after the Israelites into the sea—not so much as one of them survived!

The crossing of the Red Sea is, perhaps, the most celebrated miracle recorded in the Old Testament.  It is also one of the most contested.

Some doubt the very presence of Israelites in Egypt in ancient times.  In that case, there can have been no significant departure of Israelites from Egypt.

Some question the numbers of Israelites who are said to have crossed the Red Sea.  From a straightfoward reading of the text, there could have been around  million people.  This seems implausibly high in the light of the description of the event in this chapter.

Then again, there is doubt about which sea was crossed.  Was it the ‘Red Sea’, as we now identify it, or some other body of water?

The aim of the present article is to set such questions to one side (they are discussed elsewhere) and to ask: if the crossing took place, more or less as described in the present chapter, what actually happened?

Many discussions of the relevant texts achieve little more than paraphrase.  Even the entry in Hard Sayings of the Bible (presumably written by Kaiser) fails to offer an opinion on what kind of mechanisms may have been responsible, under God, for this miracle.

Some dismiss the biblical account as legendary.  They note, perhaps, that Ex 15 and Psa 78 are poetic in form, while neglecting to acknowledge that a historical reality might be behind the poetry.  Further, they fail to account for the fact that the primary account, in Ex 14, is not in poetic form.

Fretheim thinks that there is a historical core to this account, but that multiple sources are responsible for this

‘kaleidoscope of images: divine messengers, pillars of fire and cloud, alternating light and darkness, a strong east wind, the sea cleft in two, walls of water standing up and lying down, a dry sea canyon pathway, bogged-down Egyptian chariots, a lonely human hand twice stretched out, and a shore strewn with dead bodies…Trying to sort it out in a literal fashion, or suggesting that Israel considered the detail to correspond precisely to reality, is like retouching Renoir’s paintings to make them look like photographs.’

I think, rather, that the theological points that Fretheim wishes to draw from the text lose much of their power if the historical basis for them is watered down to that extent.

Harper’s Bible Commentary shows much more interest in the putative literary history of the accounts than in the history (or otherwise) of the events related.

The Lexham Bible Dictionary (art. ‘Exodus’) discusses the following ‘historical issues’: ‘The Number of the Israelites’, the ‘Date of the Exodus’, and ‘The Route of the Exodus’.  But there is no discussion, in the article, of the escape of the Israelites and destruction of the Egyptian army.

Some read the text in a very literal way.  Geisler (Baker Encyclopedia of Christian Apologetics), while accepting that the number making the crossing was of the order of 2 million (Num 1:45f), notes that the text implies that they completed the crossing in less than 24 hours.  He notes further that the Red Sea is, on average, some 180 miles wide.  So, Geisler would have 2 million people walking 180 miles in less than 24 hours – a walking pace of around 8 mph.  This, he thinks, is ‘a reasonable pace and sufficient time’ to make the crossing.  I think that it is implausible, to say the least.

Instone-Brewer (Science and the Bible) mentions some aspects of Humphreys’ hypothesis (summarised below), but without giving a coherent account of the event as a whole (as Humphreys does).

I turn, then, to the most thorough exploration of this miracle that I have been able to find.

Colin Humphreys (The Miracles of Exodus) reviews a number of possible natural mechanisms:

(a) A tsunami, caused by an eruption of Santorini, a volcanic island in the Mediterranean.  But no evidence of such an eruption exists around the probable date of the Exodus (1250-1300 BC).

(b) An underwater tsunami in the Red Sea.  But this would have caused severe flooding followed by rapid recession of the water; this is the opposite of what the biblical text describes.

(c) A low tide followed by a very high tide.  But tides do not form walls of water as described in Exodus.  Moroever, tides in this particular region of the world do not rise and fall rapidly, but slowly.

(d) Wind setdown.  This is a known phenomenon in which a strong wind blows across a body of water, leading to a significant rise, in one place, and fall, in another place, in the water level.  In fact, the water can be pushed back large distances, and then quickly flood back to its previous level.  This mechanism is supported by the text, which says that a strong east wind blew all night (Ex 14:21).

The mechanism of wind setdown only has a signficant effect on long stretches of water.  Both the Gulf of Suez (194 miles long) and the Gulf of Aqaba (112 miles long) satisfy this criterion.  Therefore, if the wind setdown mechanism hypothesis is accepted, the set of the crossing must have been either of these locations.

The text describes a wind blowing from the east.  The Hebrews only used the four points of the compass (not the intermediate points, such as northwest).  A wind blowing from the east would have blow across the Gulf of Suez (not along it), and so would have caused minimal setdown.  But a wind from the east (particularly if from the northeast) would have blown straight down the Gulf of Aqaba, and would have been funneled by the mountains on either side.  Thus, if the wind setdown theory is accepted, the site of the crossing would have been the Gulf of Aqaba.  We can further state with some confidence that the crossing took place at the head of this Gulf.

Humphreys adduces evidence that the prevailing wind in the Gulf of Aqaba is northeast, and that winds of hurricane force have been reported in that region.  He calculates that a wind of 80 mph, accompanied by the usual changes in atmospheric pressure, could have led to the water at the head of the Gulf receding by about one mile.

The description (in Ex 14:22 and Ex 15:8) of the water piling up like a ‘wall’ is consistent with a likely height of between 4 and 8 feet (as calculated by Humphreys).  But what are we to make of the description of a wall of water on both sides?  This can be explained in terms of a ridge of higher land – normally submerged – along which the Israelites walked.  Such ridges can be observed in the area today.

In order to explain the drowning of Pharaoh’s army, we must postulate a sudden cessation of the strong wind and a rapid return of the water to its previous level.  This is implied by Ex 14:27.  The water in the resulting ‘bore’ may have been moving at around 11 mph, covering the one mile of previous dry land in just five minutes, and easily powerful enough to knock riders off their horses.  Even the noise of the bore would have caused alarm and panic (see Ex 15:4f).

Humphreys supposes that the number of Israelites at the Exodus was around 20,000 (not the 2 million implied by some readings of the relevant texts).  This number could have been contained in a column one mile wide and just ten yeards deep.  Notwithstanding the ferocious crosswind, and the fact that they had animals, children and old people, they could made the three and a half mile crossing in two to three hours.

The Egyptians followed, but their chariots got stuck in the thick clay that has been observed at the head of the Gulf of Aqaba.  The rest of the army piled up behind these immobile chariots and then, at daybreak, the wind ceased and the water came rushing back, destroying the army.

Did Pharaoh himself drown?  The text seems to suggest so, and this is reflected too in Psa 136:15.  According to Alexander this does, however, create a problem if the exodus is to be dated to around 1447 BC, which would be in the middle of the reign of Thutmoses III (1479–1425 BC).  Ellison thinks that there is ‘no suggestion’ that Pharaoh accompanied his chariots.  Nor, he says, is there any evidence of a Pharaoh of that period meeting his death by drowning.  Humphries (who thinks that the Pharaoh in question was Ramesses II), agrees that it is unlikely that Pharaoh himself was drowned.  He notes that Ex 15:4 states that ‘the best of Pharaoh’s officers are drowned in the Red Sea’, and judges that the writer could scarcely have resisted mentioning Pharaoh himself, if in fact he had been drowned.

Clearly Humphreys’ theory is not without its problems.  One (pointed out by Steve Jeffery) is the difficulty of imagining the Israelites crossing the sea bed with a cross wind of some 80 mph.  But I have not, to date, found a better approach to explaining the scientific mechanism that may have been at work in this miracle.  And it was indeed a miracle, though (in this case) one of timing rather than one of sheer exercise of divine power.