There are many factors that make the mouth of the Columbia River especially unique. Its volume changes dramatically both daily and seasonally due to the Pacific Ocean tides and the 60 tributaries that feed the Columbia especially when snowpacks melt in the spring. The 1243 miles (2,000 kilometers) it travels, 500 miles of which are in Canada, find it winding through a wide variety of geological and climate zones. In fact, from the Columbia’s headwaters near Canal Flats, BC, it travels almost 200 miles north before turning south and finding its way to the Pacific Ocean. It has the greatest flow of any North American river entering the Pacific.