How does the author use foreshadowing regarding Katie's recollection of one of Jackson Pye's sons?

As she tells Daniel the story of the area, Katie recalls a story that Miss Vernon, the daughter of one of the original founding families, had told her about how one of the sons of Jackson Pye running away after falling in the frozen lake out of fear of his father's punishment. This recollection foreshadows the tragic events for the Pye family later in the book.