60 years later, a major underwater explosion in B.C. still fascinates

From the comfort of her office at the Museum at Campbell River, Sandra Parish looks over a span of ocean that leads to what was once called "one of the vilest stretches of water in the world."

The stretch in question is British Columbia's Seymour Narrows — the former home of Ripple Rock, an underwater mountain that was blown to smithereens 60 years ago this week.

"[Ripple Rock] was a major marine navigational hazard in a pretty important waterway on the Inside Coast," said Parish, the museum's executive director.

Claimed lives

The twin peaks of Ripple Rock lurked just below the water in the narrow waterway, leaving only three metres of clearance at low tide. The peaks also created giant whirlpools that sucked smaller boats below and threw larger ones off-course. 

Ripple Rock claimed the lives of at least 114 people on as many boats, which ranged from pleasure crafts to large barges full of supplies heading north to Alaska and Haida Gwaii.

The explosion on April 5, 1958, that blew Ripple Rock to bits was a major engineering feat years in the making. It was also one of the first events to be broadcast live across the country, forever etched in the minds of the nation's citizens huddled around their new televisions.

B.C.'s deadly Ripple Rock blown up

67 years ago

Duration 3:56

B.C.'s deadly Ripple Rock is blown up in the world's largest non-nuclear peacetime explosion.

Despite presenting itself as a major marine hazard, many in B.C. opposed Ripple Rock's destruction, according to the museum. They hoped the underwater mountain could help connect a bridge from Vancouver Island to the mainland.   

But the federal government decided that making the waterway safer was a bigger priority, because it provided a channel linking the northern part of the continent to the rest of Canada and the U.S.

Beginning in 1943, engineers made several attempts at dismantling Ripple Rock. Eventually, work began in 1955 to built shafts and tunnels under the water and fill them with explosives.

"At the time everyone was very, very concerned about what this was going to cause, what impact there might be," Parish said.

Some local residents boarded up their windows and headed for higher ground on the morning of the explosion, worried about tidal waves and aftershocks.

Broadcast live

The blast shot 635,028 tonnes of rock and water 305 metres into the air over the course of just 10 seconds, but most people felt and heard nothing. Even aquatic wildlife was deemed unperturbed, according to Parish.

Residents did, however, see the explosion burst across the screens of their televisions. CBC News aired the event live across the country using relatively new broadcast technology.

Parish said that it's because of the television coverage that many people still remember the event.

She said people are still so fascinated by Ripple Rock that internet searches on the subject bring in some of the biggest traffic on the museum's website.

Today, as she looks out her office window, Parish sees the many vessels that still navigate the waterway on their way north — many of them cruise ships, fishing boats and tugs pulling logs.

What she doesn't see is the swirling waters caused by the mountain lurking beneath, blown away long ago to make way for safe passage.