Sharkfin Tower is a summit in North Cascades National Park, rising above glaciers between Forbidden Peak and Boston Peak and draining into the Skagit River system. Climbers prize its granite and have established notable routes on its ridges and faces, including ascents made in 1947, 1968, and 1990. Its marine west coast climate brings heavy precipitation, winter avalanche danger, and clearer but still serious summer alpine conditions. The peak also reflects the broader geologic history of the North Cascades, shaped by tectonic, volcanic, and glacial forces over millions of years. In 2005, a climbing accident there caused three deaths and one injury.