Ripple Rock

The moment of the explosion from a hilltop.

Ripple Rock is an underwater mountain that had two peaks (9 feet and 21 feet below the surface) in the Seymour Narrows of the Discovery Passage in British Columbia, Canada,[1] a part of the marine trade route from Vancouver and coastal points north. The nearest town is Campbell River. Only 2.7 metres (9 feet) underwater at low tide, it was a marine hazard in what the explorer George Vancouver described as "one of the vilest stretches of water in the world."[2][3] The hazard was not only hitting the rock but also big, dangerous eddies caused by tidal currents round the rock.[4] Ships using the strait preferred to wait until slack tide.

Its top was removed by a planned explosion on 5 April 1958.[5] This is a National Historic Event in Canada. The Ripple Rock explosion was seen throughout Canada, live on CBC Television. It was one of the first live coast-to-coast television broadcasts of an event in Canada.[6]

It was so named in 1862 by Captain Richards, RN,[7] because its summits were about at sea level and made a prominent standing wave in the fast tidal current of the strait.


USS Saranac

The first known large ship to fall prey to Ripple Rock was the sidewheel steamer Saranac in 1875, as it was heading north to Alaska.[8] At least 20 large and 100 smaller vessels were badly damaged or sunk between then and 1958. At least 110 people drowned in these accidents.