The sea returns and the waves destroy the pharaoh’s army.

Illustration by the English artist John Martin made in 1833.

According to the book of Exodus, the Israelites began their trek out of Egypt once the plagues had persuaded the pharaoh to set them free.  However, before long the pharaoh had a change of heart and ordered his army to pursue them.  With their backs to the Red Sea all seemed lost until God again interceded and caused the waters to part.  The Israelites were so able to walk across the seabed, but when the Egyptian army tried to follow the waters returned and they were washed away.

It is possible that this was another Exodus event also caused by the Thera eruption.  The Thera volcano was on the island of Santorini and geological surveys have shown that the massive eruption caused a large part of the island to collapse into the sea, creating a series of gigantic tsunami or tidal waves that might explain the Old Testament account.

Firstly, it seems that the event did not happen at the Red Sea to the east of Egypt but at another stretch of water in the northeast Nile Delta.  It is now recognized that the name Red Sea is actually a mistranslation.   The original Hebrew Bible describes the place where the Israelites crossed out of Egypt as Yam Suph – “The Reed Sea”.  This was the old name for Lake Manzala on the Mediterranean coast at the extreme northeast of Egypt.   Its modern name is somewhat misleading as it is actually open to the sea.  However, this was not always the case.  In ancient times, when sea levels were lower, it was divided from the Mediterranean by a narrow ridge of dry land some 30 miles long, broken by a short stretch of water at high tide.  At low tide this became a causeway that could be crossed on foot.

This is a route that makes sense.  The Bible tells us that the Israelites were enslaved in an area called Goshen in the north-east of Egypt, and the best way to escape Egypt from here, avoiding the patrolled border, would have been to head north and then cross the Manzala causeway at low tide.  If a tsunami had hit the coast when the Egyptians were following the result would have been very much as the Bible describes.

Route of the Exodus from Goshen, avoiding the patrolled Egyptian border with the wilderness.

Preceding the arrival of a tsunami the coastal sea level often drops.  (It is basically the same phenomenon that causes the sea to withdraw before the breaking of a normal wave, only over a longer duration).  Such a phenomenon may have worked to the Israelites’ advantage.  If a section of the Manzala causeway usually under water had been exposed by the pre-tsunami conditions, then the Israelites could have crossed in the way the Bible relates:  "and the waters were divided" (Exodus 14:21).  This is an excellent description of what could have happened at the Manzala causeway, with the waters of the Mediterranean having divided from the waters of the Lake Manzala.  The Israelites could have made it safely across and, if the timing was right, the pursuing soldiers might have been attempting to follow when the tsunami hit.

And the waters returned and covered the chariots, and the horsemen and all the host of Pharaoh that came into the sea after them; there remained not so much as one of them. (Exodus 14:29.)

The dreadful tragedy in South Asia on December 26, where an earthquake off the west coast of northern Sumatra caused waves as high as twenty feet to crash into coastal areas of Sri Lanka and India, over six hundred miles away, shows both how devastating and far reaching the destructive power of tsunami can be.  Geologists have estimated the magnitude of the similar tsunami caused by the Thera eruption:  huge waves, well over twenty feet high, would easily have reached the Egyptian coast which was only a little over four hundred miles away.

Click on the image to the right for an animated simulation of the estimated size and speed of the tsunami that resulted after the Thera eruption.  Unfortunately, the coast of Egypt is not shown on this simulation, which is just off the map to the south east.   However, it does give an idea of the power of the tsunami that was about the thrash the low-lying area of the Egyptian Nile Delta.