Remembering Seattle’s ‘Great Ravenna Sinkhole’

A sinkhole that opened suddenly Thursday night beneath the bedroom a Florida home – swallowing a man in his bed – is rekindling memories of a massive sinkhole in Seattle decades ago.

Seattle historian Feliks Banel remembered “The Great Ravenna Sinkhole” in a conversation Friday with KIRO Radio’s Luke Burbank Show.

The hole collapsed on the night of Nov. 11, 1957 in Seattle’s Ravenna neighborhood at Ravenna Blvd. between 16th and 17th Avenues NE. Caused by the failure of a six-foot diameter sewer pipe break, at the time it was the biggest one of its kind.

Gallery: Remembering Seattle’s “Great Ravenna Sinkhole”

Repairs took two years to complete, including first a sewer bypass through Ravenna Park, then stabilizing the broken trunk with a newly devised grout material and re-boring the tunnel.

“They think it might have been damaged in the earthquake in 1949 and then gradually the dirt – 145 deep down this pipe was – the dirt started to gradually wash away,” Banel said.

The hole measured 60 feet deep, 120 feet wide, 200 feet long. Somewhat miraculously, no one was injured and not a single home was damaged. Dozens of people were evacuated from 10 houses in the neighborhood north of the University District.

“A few days after the initial collapse there was a bigger collapse, the hole expanded but none of the houses were damaged,” Banel said.

Today, you’d never know the cave-in ever happened. Banel visited the area today and said all of the houses are still there, many looking exactly like they did 60 years later

“Pretty amazing repair,” Banel said. “They had to bypass this part of the sewer line. They had to build something like a 5,000 foot long bypass and then get in there and put in the fill and rebuild the street and I looked around I don’t see any evidence. The sidewalk, the curbs, everything looks like it’s been there forever.”

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