Landslide that hit Port Alice in 1975: 'All we saw was rock and mud'

Vancouver Island has a number of sites prone to slides, research paper says

 

Water, mud and boulders poured through Port Alice, on northern Vancouver Island, one morning in November 1975 and Dugald (Mac) Macmillan saw it happen while he was on duty as a Mountie.

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The mudslide in Washington state has brought back memories of the Port Alice slide.

Macmillan was one of two Mounties at the Port Alice detachment when a mudslide and torrent of water tumbled through town.

He was driving away from town when he heard a voice crackling over the radio that Port Alice was in peril. He turned around and rushed back.

It had been a wet November with early snowfalls that came halfway down the mountains, Macmillan said. “The freezing level went to a high ceiling and it melted that snow and saturated everything,” said Macmillan, who returned to Port Alice after retiring from the RCMP.

The slide hit about 11 a.m. at Rumble Beach, as it was known then, a seaside slope on an alluvial fan, the path of previous slides.

Macmillan’s vehicle was stopped on the road by oncoming debris. “All we saw was rock and mud — it was coming between the houses and it was moving very slowly.

“The water had gone down Rupert Street, around the corner and through some strata houses on Haida Street. People just opened their doors and let the water go through the houses.”

Vancouver Island is “uniquely vulnerable” to landslides, Vancouver Island University researchers have found.

Port Alice has been hit by several significant damaging slides, and is now protected by a series of earth berms.

The berms were built after landslides in 1973 that shoved a house off its foundation and the one Macmillan witnessed in 1975. There were 2,200 people in town at the time, making a living logging or at the mill. Today the resource industry jobs have all but dried up and the population hovers around 800.

No one was killed in either of the two slides, said MacMillan. The slides “just made a mess of everything.”

Landslides are at the top of the list of hazardous threats to Port Alice, according to a 2011 municipal report.

The berms helped deflect debris from a large slide in December 2002. Still, the town remains vulnerable — another slide in September 2010 prompted the evacuation of part of the town.

Contributing factors to slide danger on Vancouver Island include a rugged and steep landscape combined with high rainfall and seismic activity.

Fine sediments made up of silts and clay occur primarily along the coastline in areas such as the Georgia Basin, Island View Beach on the Saanich Peninsula, Departure Bay in Nanaimo and Wilbar Bluffs in Courtenay, says an article by the geology department at Vancouver Island University. These deep deposits “are notoriously unstable and vulnerable to wave erosion,” it says.

Slumping is very common along where land and water meet, and is particularly common on the east coast of Vancouver Island where urban development is the greatest.

Most people don’t pay enough heed to building homes on steep but potentially unstable cliffs, the article says. “In the inevitable attempts for a better view, many of us place ourselves at risk by building a house or structure too close to a slumping riverbank or an eroding oceanside cliff,” says the article. “These threats can seem stable for years and then suddenly fail with renewed activity.”

smcculloch@timescolonist.com

 

> Death toll from Washington state mudslide climbs to 14, with 176 listed as missing, A2

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