Veterans of river travel know that waterways can be a creature of movement in more ways than one. In mountain country, rainfall in the hills all goes downhill by gravity and ends up ocean-bound via the river system. In Alaska’s arctic specifically, most river flow is dominated by snow melt or rain, unlike many of the glacier melt rivers of the interior. So when the rain comes in abundance while on a wilderness river trip, vigilance is prudent. While on the Marsh Fork of the Canning river in July, plenty of rain fell in the mountains of the Brooks Range, creating a swollen river. Note the two pictures below which reflect the rapid change that can happen as a result of heavy rains.