Lentorama 2023: It Happened on Holy Saturday

Day 30: Ripple Rocked

Ripple Rock is an underwater mountain in the coastal waters of British Columbia, located in Discovery Passage, the strait between Vancouver Island and the Discovery Islands. It has two peaks, both underwater at low tide, and the presence of these peaks caused significant eddies from currents passing them as water receded. This posed a significant threat to ship traffic, with many ships choosing to wait until slack tide to pass.

The Canadian government decided the best way to solve this problem and open up the passage to shipping regardless of the tides, was to blow Ripple Rock up. Attempts in the 1940s proved unsuccessful, as barges meant to place charges were ripped from their anchoring cables. After studying the problem, it was determined that the best approach to this was to tunnel vertically from Maude Island, and then up into the twin peaks. This process took nearly three years to complete.

Once the tunnels were dug, over 1200 tons of Nitramex explosive were placed within them, and on Saturday, April 5, 1958, the explosives were detonated during a live coast-to-coast broadcast. Water and debris blew nearly 1000 feet into the air, with chunks of rock landing on both sides of the narrows. The height of both peaks had been significantly reduced, with clearance at low tide going from 10-20 feet to 45-50 feet.