What does Jim warn Chris about in Into the Wild?

When Alex tells Jim that he plans to go to the end of a little known path that peters out into the wilderness north of Mt. McKinley, Jim does his best to dissuade him. He tells him the hunting isn’t good there, and the grizzlies are fierce—but Alex won’t budge. He even offers to take Alex to Anchorage to buy him some better gear, but Alex says he’ll be fine with what he has. He also tells Jim that he doesn’t have a hunting license, and no one knows where he is going—he hasn’t spoken to anyone in his family for nearly two years. Jim convinces Alex to take his boots and some sandwiches his wife made for him, then he takes a picture for Alex at the trail head and leaves him there on April 28, 1992.