To find the white bear, you climb an ice wall north of the map, to the left of a nomad trading post. To trigger part 2, head left towards a firewatch tower. When you get told to follow the bears tracks, head far right, past a log cabin and fire watch tower, you'll find a cave. You'll be told to trap or kill the bear. Kill the bear to finish Blane's story to unlock achievement. You'll also find Blane's camping supplies, Large tent, Cooking Station, Camp guard you'll need to fully upgrade the Campsite.