I think the volcano eruption make more sense that most theories.
Velokowski? thought that Venus was a comet that was captured by the sun, and that its passage caused great disturbances. His explanations of the plagues using this theory was pretty far out.
I remember a National Geographic article in the 1950's that talked about grasshoppers in the Sinai desert that excrete a carbohydrate that is edible, and NG author conjectured that this was the manna of Exodus. I think that article also stated that a reversal of tides phenomenon is known in the Red Sea area that causes waters to retreat occasionally, making it possible to cross.
As Moses was in exile in that area, he probably was familiar with these phenomena.
The most interesting plague is the death of the first born.
Not sure volcanos can explain that, although the deaths of those who didn't keep the same hygiene rules the Hebrews did would explain why mostly Egyptians died in a time of flies and boils, but not why the first born would be affected only.
Velikovsky was nuts. The planet Venus is just slightly smaller than the earth. Comets are vastly smaller bodies than an earth-sized planet...there is simply no way that a comet could have transmogrified itself into the planet Venus.
I have some problem with the volcano part. If I recall correctly, they were led thru the wilderness by the pillar of smoke by day and fire by night for 40 years. That seems a bit long for one volcano to spew.
If you read Ages in Chaos you will find the following;
ISAIAH 43:16 Thus saith the Lord, which maketh a way in the sea and a path in the mightly waters;
20...I gave waters in the wilderness, and rivers in the desert, to give drink to my people, my chosen.
In the Book of Exodus it is said that Moses was commanded:
EXODUS 4:22-23 And thou shalt say unto Pharaoh, Thus saith the Lord, Israel is my son, even my firstborn.
...and if thou refuse to let him go, behold I will slay thy son, even thy firstborn.
The 'chosen' are here called 'firstborn'. If Israel was the firstborn, revenge was to be taken against Egypt by the death of its firstborn. But if Israel was the chosen, then revenge was to be taken against Egypt by the death of its chosen.
'Israel, my chosen' is ISRAEL BECHIRI, OR BECHORI.
'Israel my firstborn,' is ISRAEL BEKHORI.
It is the first root which was supposed to determine the relation between God and his people. Therefor: 'at midnight the Lord smote all the firstborn in the land of Egypt' (Exodus 12:29) must be read 'all the select of Egypt' as one would say, 'all the flower of Egypt' or 'all the strength of Egypt'.