God Yahweh Allah was a volcano.

[The Grand Nudger]

Sure, except that we know that the group which became "Hebrew" or "Jewish" depending on who you ask, were homegrown Canaanites. Recent (and some old hat stuff) evidence suggests that exodus is a mythical account, and part of a tradition of myths, that have been leveraged as revisionist history ( a concept you clearly understand, but about whose origins you seem unclear).

Sometimes a narrative really rings out to us. The exodus narrative (at it's heart) is one of those narratives. It's a damned good story. We have become emotionally attached to it. Still, there's no shame in saying that something is "just a story" until you have reason to believe otherwise. I'm not trying to stifle your desire to theorize or explain these things, only suggesting that you spend that time and ability working on something we actually need explanations for.

Let's take a look at what wiki has to say, shall we?

"Genesis is perhaps best seen as an example of "antiquarian history", a type of literature telling of the first appearance of humans, the stories of ancestors and heroes, and the origins of culture, cities and so forth.[16] The most notable examples are found in the work of Greek historians of the 6th century BCE: their intention was to connect notable families of their own day to a distant and heroic past, and in doing so they did not distinguish between myth, legend, and what we would facts.[17] Jean-Louis Ska calls the basic rule of the antiquarian historian the "law of conservation": everything old is valuable, nothing is eliminated.[18] Ska also points out the purpose behind such antiquarian histories: antiquity is needed to prove the worth of Israel's traditions to the nations (the neighbours of the Jews in early Persian Palestine), and to reconcile and unite the various factions within Israel itself"

Which was used to support the book of Exodus.

"The book of Exodus is not historical narrative in any modern sense.[11] Modern history writing requires the critical evaluation of sources, and does not accept God as a cause of events.[12] But in Exodus, everything is presented as the work of God, who appears frequently in person, and the historical setting is only very hazily sketched.[13] The purpose of the book is not to record what really happened, but to reflect the historical experience of the exile community in Babylon and later Jerusalem, facing foreign captivity and the need to come to terms with their understanding of God"

One could consider Exodus a sequel to the narrative nearest the end of Genesis (The suggestion is made that bones should be taken back to the holy land, packed up in Egypt and ready to go).

"Joseph, Jacob's favourite son, is sold into slavery in Egypt by his jealous brothers. But Joseph prospers, and when famine comes he brings his father and his brothers and their households, seventy persons in all, to Egypt, where Pharaoh assigns to them the land of Goshen.[Gen 46-47] Jacob calls his sons to his bedside and reveals their future to them[Gen 49] before he dies and is interred in the family tomb at Machpelah. Joseph lives to see his great-grandchildren, and on his death-bed he exhorts his brethren, if God should remember them and lead them out of the country, to take his bones with them. The book ends with Joseph's remains being "put in a coffin in Egypt."

The myths need only be consistent to each other, not reality.

http://en.wikipedia.org/wiki/Book_of_Genesis
http://en.wikipedia.org/wiki/Book_of_Exodus

(I'll defend Wiki until the day I die)