The Barrier

The high vertical cliff at the Barrier has long been debated regarding its potential for catastrophic collapse. Large-scale collapse of The Barrier is also extremely unlikely, but could potentially block the Cheakamus River. A blockage of this nature increases the possibility of a debris flow that could affect all of Paradise Valley, with the most intense impacts occurring near the District’s northern boundary. Despite public misconceptions, there is no scientific evidence that collapse of the Barrier could drain Garibaldi Lake or cause extreme flooding in downstream neighbourhoods along the Squamish River.

This hazard has been sensationalized in various media sources (Wikipedia, newspaper articles, youtube videos) which has compounded the common misconception. The more realistic hazard is that rockfall from the barrier could block the Cheakamus River which could then cause an outburst flood. Even this is a very low probability event and has been concluded to pose limited flood risk within District boundaries due to significant upstream attenuation (storage, smoothing out of peak flows). The consequences are much higher for areas immediately downstream of Rubble Creek.

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