Qualla: Ripple Rock

Ripple Rock: Introduction

Sat, 21 Mar 2026 00:00:00 GMT

Photo credit Lett, Sherwood (1895-1964), Public domain. At 9:31:02 on the morning of April 5, 1958, the twin peaks of Ripple Rock ceased to exist. One thousand two hundred and seventy metric tonnes of Nitramex 2H explosive, packed into shafts tunneled up from beneath the seabed, detonated in a single coordinated blast. Six hundred and thirty-five thousand tonnes of rock and water erupted 300 metres into the air, raining debris on both shores of Seymour Narrows. Canadians watched it happen live on television -- one of the first coast-to-coast broadcasts of a real-time event in the country's history. The underwater mountain that had terrorized mariners for more than a century was gone.

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Image: Lett, Sherwood (1895-1964) | Public domain

Ripple Rock: One of the Vilest Stretches of Water

Sat, 21 Mar 2026 00:00:00 GMT

Photo credit Lett, Sherwood (1895-1964), Public domain. Explorer George Vancouver noted Ripple Rock as early as 1791, describing the surrounding waters as "one of the vilest stretches of water in the world." The twin-peaked seamount sat in Seymour Narrows, the tightest section of Discovery Passage, where the channel narrows to 750 met...

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Image: Lett, Sherwood (1895-1964) | Public domain

Ripple Rock: Decades of Failed Attempts

Sat, 21 Mar 2026 00:00:00 GMT

Photo credit Lett, Sherwood (1895-1964), Public domain. As early as 1931, a marine commission recommended removing Ripple Rock, but the idea had powerful opponents. In the 1860s, planners had proposed using the rock as a mid-support for a bridge linking Vancouver Island to the mainland at Bute Inlet, and this vision persisted for deca...

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Image: Lett, Sherwood (1895-1964) | Public domain

Ripple Rock: Tunneling from Below

Sat, 21 Mar 2026 00:00:00 GMT

Photo credit Carport, CC BY-SA 3.0. In 1953, the National Research Council of Canada commissioned a feasibility study for a radically different approach: tunneling from nearby Maud Island, drilling horizontally beneath the seabed to reach the base of Ripple Rock, then drilling upward into the twin peaks to plant ex...

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Image: Carport | CC BY-SA 3.0

Ripple Rock: The Blast Heard Across Canada

Sat, 21 Mar 2026 00:00:00 GMT

Photo credit Lett, Sherwood (1895-1964), Public domain. The Royal Canadian Mounted Police cleared everyone within three miles. Engineers and the television crew were sheltered in a bunker. At 9:31 in the morning, the charges fired. The explosion displaced 635,000 metric tonnes of rock and water. Debris arced 300 metres skyward and fel...

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Image: Lett, Sherwood (1895-1964) | Public domain

Ripple Rock: After the Blast

Sat, 21 Mar 2026 00:00:00 GMT

Photo credit Lett, Sherwood (1895-1964), Public domain. Seymour Narrows is still no place for the careless. Even without Ripple Rock's peaks, the currents remain fierce, and vessels continue to time their transits carefully. In March 1981, the freighter Star Philippine ran aground in the narrows, a reminder that the water itself is th...

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Image: Lett, Sherwood (1895-1964) | Public domain