Why did Tom Venn's family move to Alaska in the novel, Alaska?

Tom Venn moved to Alaska with his parents, who were fugitives from Chicago. His father was killed while driving a sled. Tom was in his teens when he first moved to Alaska. He opened a general store for Ross and Raglan and eventually a series of salmon canneries. He married Lydia Ross and made Ross and Raglan one of the biggest business entities. The Venn family was prominent in both Seattle and Alaska.