The name for Shannon Falls in the Squamish language is Kwékwetxwm which means “rumbling noise”, referring to the sound of the water as it rushes over the rocks. People from the nearby village of Stá7mes use this area to gather resources and hunt for animals. It is also said to be a place where Squamish medicine people trained. Kwékwetxwm is also known as a place where the famous Xwechtáal cleansed himself and gathered strength as he chased the two-headed serpent called Sínulhḵay̓.
The story goes that there was a huge two-headed serpent called Sínulhḵay̓ who terrorized the Squamish peoples, so the young Xwechtáal set out to find and kill it. He saw that Sínulhḵay̓ went up Siy̓ám Smanít (the Stawamus Chief Mountain) and left a large black streak in his path, but Xwechtáal could not follow it because of the serpent’s dark power. Instead, Xwechtáal went up the mountain pass, stopping at many creeks, rivers, and lakes to clean himself and gain strength. He did this at Kwékwetxwm too.

Finally, Xwechtáal found Sínulhḵay̓ in a lake in the mountains. He watched the serpent and noticed that one of his heads would be awake during the day while the other head slept. Xwechtáal made four sharp spears and a raft. He rowed to the head that was awake and stabbed it with two spears. This woke up the other head who was very angry. Xwechtáal rowed across to the second head and speared it with one spear. Sínulhḵay̓ dove under water but Xwechtáal threw the last spear and got the serpent right in the head! Sínulhḵay̓’s body fell to the bottom of the lake and blocked an underwater tunnel, causing the water to rise. Xwechtáal fell asleep and when he woke up he was on top of a mountain. He waited for the water to go down, and climbed down the mountain to look for the body of the dead serpent. He found the bones of Sínulhḵay̓ and took one of them which gave Xwechtáal magical powers. Xwechtáal returned to the people and showed them his new powers. When he returned, he also realized that even though he thought he was only gone for a few days, his journey to kill Sínulhḵay̓ had actually taken him 10 years!