The Biblical image of Moses raising his arm to part the waters of the Red Sea is one of the most enduring to emerge from the Old Testament. But what has long been thought to be either a fable or a miracle may in fact have happened – as researchers postulate theories as to how and where such an event might have taken place.
The Biblical Account of the Red Sea Crossing
The Bible (Exodus Chapter 14) offers some specific meteorological information on the crossing of the Red Sea. After Moses stretched out his arm, ‘the Lord drove the sea back by a strong east wind all night and turned the sea into dry land.’ The Israelites were then able to pass through the sea, ‘the waters forming a wall…on their right and on their left.’]
For the pursuing Egyptians, however, there was no such convenient dry route. When the Israelites, safe and dry, reached the other side, Moses once again raised his arm, with devastating effect. ‘At dawn the sea returned to its normal depth…the waters returned and covered the chariots and the chariot drivers…not one of them remained’ (Holy Bible, New Revised Standard Version).
Parting the Red Sea: Examining the Possibilities
In 1992, a paper by Doron Nof and Nathan Paldor looked at possible scientific explanations for the parting of the Red Sea as set out in the book of Exodus. They considered two options – a tsunami generated by an earthquake or other event (such as landslide or volcanic eruption) and a mechanism called ‘wind setdown’ in which winds drive back the sea.
Although the Red Sea region is highly seismically active, Nof and Paldor rejected the tsunami as the most likely explanation in favor of the wind setdown, which fits better with the description of the event laid down in Exodus. Wind setdown is the opposite of a storm surge, and occurs when wind (sometimes in combination with tides) drives water abnormally far from the coast.
Nof and Paldor concluded that the Biblical description of an overnight easterly wind at a (not excessive) speed of 20ms-1 would have generated a sea level drop of over 2.5m at the northern end of the Red Sea. Combined with the possible existence of a submarine ridge, this would have allowed the Israelites a land bridge and time to cross.
The destruction of the pursuing Egyptians (a shortcoming of the tsunami model) is also explained by wind setdown. A sudden drop in the wind speed, or a change in the wind direction, would have allowed the waters to rush back rapidly. Nof and Paldorf’s calculations suggest that the dry area could be completely flooded in as little as four minutes, leaving no hope of escape for anyone still on the dried-out ridge.
Red Sea Crossing: Refining the Location With Computer Simulations
In 2010, further work was undertaken on the theoretical possibility of a scientific explanation for the Red Sea crossing. Using computer simulations, Drews and Han focused upon historical topography and considered Nof and Paldor’s proposals. Also following the theory of wind setdown, they considered alternative locations and found what they considered to be a better fit elsewhere.
Rather than the location at the north end of the Red Sea/Gulf of Suez favored by Nof and Paldor, they identified a site on the Mediterranean coast, at the Lake of Tanis. Here, computer modelling demonstrated that the former coastline would, under a wind setdown of 28ms-1, open up a 3-4 kilometer-long land bridge which would remain open for around four hours.
Red Sea Miracle: The Truth?
There are obvious difficulties in drawing a firm conclusion about the passage across the Red Sea. The Bible’s information can be interpreted in different ways and is vague about location. Also, the topography of the Red and Mediterranean Seas and their coasts has changed as sea levels fluctuate over periods of thousands of years.
Scientific research indicates, however, that such an event might have taken place as described purely through the natural mechanisms of wind setdown and a favorable topography. Whether such an event happened at the behest of the Lord, as the Bible maintains, or whether the Israelites were simply very lucky remains, of course, a matter for much greater, and less scientific, debate.
Drews, K., Han, W. “Dynamics of Wind Setdown at Suez and the Eastern Nile Delta” PLoS ONE. (2010).
Holy Bible: New Revised Standard Version. Hendrickson Bibles.
Nof, D., Paldor, N.”Are there oceanographic explanations for the Israelites’ crossing of the Red sea?” Bulletin American Meteorological Society. (1992).