Old Fort landslide evacuees can go home today

Most Old Fort landslide evacuees are finally able to go home.

The Peace River Regional District board lifted the evacuation order for most of the community at a special meeting on Sunday.

"This has been really difficult for everyone involved and we're very happy to be able to move forward," said board chair Brad Sperling after the meeting.

Some homes, however, stil remain on evacuation order or alert. That includes 7605 Old Fort Road (order) and 6975 Old Fort Road, 9820 River Drive, and 7583 Old Fort Road (alert).

Residents are available to return home starting at 3 p.m. Sunday.

The board was originally hoping to have residents return home starting at 12 p.m. Sunday, but had to push the time back three hours due to the heavy snowfall that's fallen in the area. 

Properties at 9909 240 Road and 9911 240 Road, which are gravel pits and have no residents, remain under evacuation order. Properties at 6963 265 Road, 6933 265 Road, and 9819 240 Road also remain under evacuation alert at this time. 

There will be a future analysis to come on the properties that remain under evacuation order or alert.

More than 150 residents were ordered to evacuate on Oct 7, one week after the landslide cut off power and road access to the community.

The board was acting on the findings of a preliminary geotechnical study of the landslide and the risk of it continuing to move and spread.

Both Westrek Geotechnical Services and BGC Engineering agreed that most homes in Old Fort were not at imminent risk of being impacted by the landslide.

However, both caution that the slide is still active and expected to move and shift, with a warning for spring. Both recommended continued monitoring of the slide.

“The latest results show minimal movement in more than one week, indicating that large scale movement has ceased; however, the landslide is not considered inactive,” Westrek wrote in its report. 

“Conditions on the landslide can change with little to no warning; therefore, the entire landslide mass, including the rockslide, earth flow, and both adjacent landslides, should be considered to be at imminent likelihood of movement.”

The ministry of transportation and infrastructure has built a temporary road through the landslide debris and has set up monitoring points. Westrek expects spring freshet to "severely" damage that road.

The slide was last estimated at more than eight million cubic metres, and had been moving slowly for months before it let go in a massive collapse on Sept. 30. It destroyed a wide swath of Old Fort Road and cut utility transmission lines, and severely damaged one home. 

The slide began at the south end of a gravel pit that had been operating on the hillside above Old Fort, “with sudden movement” in the shale bedrock that extended 160 metres into the pit from the edge of the hill.

“The ground within the pit dropped more than 10 m and slid approximately 12 m to the south, setting in motion a complex series of other landslides," according to Westrek.

Work at the gravel pit should only resume when when a safe work plan has been approved by the province, Westrek stated.

"Work directly on the landslide within the pit should be limited to removal of existing stockpiles," the company wrote.

BGC Engineering, in its peer review of Westrek's findings, said it agreed with the assessment that most homes in Old Fort aren't at imminent risk of impact from the landslide. It disagreed with some of the company’s assessments about properties it believes are still at risk. 

“Our preliminary opinion is most homes are not likely to be impacted by damaging landslide movements associated with the Old Fort Landslide prior to significant snow melt and/or rainfall in spring 2019,” BGC wrote in its report.

BGC said residents should be warned of the hazards that remain.

“The Old Fort Landslide event has resulted in several deep ground cracks within and around the margins of the landslide,” BGC wrote.

“Many of these cracks are difficult to see and could pose a safety hazard to persons and pets walking near them.”

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