{"id":29065,"date":"2018-10-25T06:27:42","date_gmt":"2018-10-25T06:27:42","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=29065"},"modified":"2018-10-25T06:27:42","modified_gmt":"2018-10-25T06:27:42","slug":"old-fort-landslide-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/10\/25\/old-fort-landslide-1\/","title":{"rendered":"The Old Fort landslide in British Columbia"},"content":{"rendered":"

The Old Fort landslide in British Columbia<\/h4>\n

Earlier this month the small community of Old Fort, near to Fort St John in British Columbia<\/a>, western Canada, was evacuated due to movement of the Old Fort landslide.\u00a0 In addition to potentially threatening some properties, the Old Fort landslide severed the only access road to the community.\u00a0 The landslide is large but quite slow moving. Alaska Highway News has a splendid gallery of images of the landslide<\/a> released by the Peace River Regional District, which includes this image of the earthflow component of the landslide as it crosses the highway:-<\/p>\n

\"Old

The Old Fort landslide in British Colombia. Image from Peace River Regional District via Alaska Highway News<\/a>.\u00a0 Note the tension crack on the right side of the hillock in the centre left of the image.<\/p><\/div>\n

.<\/p>\n

This phase of movement of the landslide initiated on 30th September, although there is considerable evidence that it had been moving prior to this date.\u00a0 Local geologists, from Westrek Geotechnical Services<\/a>, who have been studying the landslide, have diagnosed it as failure in bedrock<\/a> in the area of a gravel pit operating on the hillslopes above Old Fort.\u00a0 The initial failure triggered a second failure in terrain to the west, allowing the development of an earthflow lobe that followed a pre-existing gully.\u00a0 The slide has a volume of about 8 million m\u00b3. This image, also from Peace River Regional District, gives an idea of the scale of the problem.\u00a0 Whilst the main earthflow is clear, the tension cracks and scarps extending across the hillslopes are also evident:-<\/p>\n

\"Old

Annoted photograph of the Old Fort landslide in Canada. Image from Peace River Regional District via Alaska Highway News<\/a>.<\/p><\/div>\n

.<\/p>\n

Whilst this image shows the source area of the current main part of the Old Fort landslide:-<\/p>\n

\"Old

The source area of the Old Fort landslide. mage from Peace River Regional District via Alaska Highway News<\/a>.<\/p><\/div>\n

.<\/p>\n

A temporary road is currently under construction across the landslide, and work continues to monitor and analyse its behaviour.\u00a0 As usual it is proving very challenging to forecast its likely future behaviour, as has been the case in the Mannen landslide in Norway<\/a>.\u00a0 Winter is coming, and of course following that will be the snowmelt season in the spring, when groundwater levels could rise.\u00a0 Unfortunately this landslide could prove to be a challenge for some time yet, to the inevitable frustration of the inhabitants of Old Fort.<\/p>\n","protected":false},"excerpt":{"rendered":"

The Old Fort landslide in British Columbia is an 8 millon cubic metre earthflow that has caused the evacuation of the village of Old Fort<\/p>\n","protected":false},"author":22,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[469],"class_list":["post-29065","post","type-post","status-publish","format-standard","hentry","category-landslide-report","tag-featured"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29065","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=29065"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29065\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=29065"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=29065"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=29065"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}