22 September 2016

Wye River: landslides in the aftermath of a forest fire in Australia

Posted by dr-dave

Wye River: landslides in the aftermath of a forest fire in Australia

The small town of Wye River, on the coast of Victoria in the southeast corner of Australia, suffered devastating forest fires in the summer of 2015.  Wye River itself lost 98 homes – one third of the town – and a further 18 were lost in nearby Separation Creek.  Over Christmas last year a desperate battle was fought to save the remainder of the town, successfully, but images of the aftermath remain horrifying:

Wye River

The aftermath of the Wye River fire, via Herald Sun and Aaron Francis

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A well documented hazard in the aftermath of a large fire is the potential for increased landslides.  Last week this area suffered heavy rainfall, triggering multiple landslides along the Great Ocean Road, which passes through the town (and can be seen in the image above).  More than 150 landslides and rockfalls have been reported along the road in the last three weeks, and the highway remains severely restricted:

Wye River

A landslide on the Great Ocean Road near Wye River, via Twitter

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The most serious issue though is situated between Wye River and Separation Creek, where a landslide of about 1,000 cubic metres has developed, opening a large tension crack:

“The Paddy’s Path was impacted by a 35-metre tension crack and is posing a very significant landslip risk,” the EMV said, after VicRoads engineers inspected the path between Wye River and Separation Creek on Thursday.  Wye River General Store’s Shaun McKinlay said the situation was “all too familiar” for residents, who faced the isolation of road closures, and the worry of not knowing what was going to happen next for the second time in less than 10 months.  Mr McKinlay said on Friday he understood the crack becoming a landslide was an “event that’s going to happen, they just don’t know when”.

This is a GGoogle Earth image of the location of Paddy’s Path in Wye River:

Wye River

Google Earth image of the location of the Wye River landslide. This image predates the fire.

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This image shows the area burned in the fire of December 2015:

Wye River

The aftermath of the December 2015 fire in Wye River, via Herald Sun and Hamish Blair

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It is clear that the area affected by this landslide is exactly that burned in the fire last year.  The link between the two is of course not a coincidence.  That forest fires are becoming increasing problematic as a result of climate change is also well established in Australia.  The implications for the future in terms of landslides are clear.

Similar posts likely to be of interest:
  1. Australian wildfires and risks of increased erosion rates
  2. Emergency assessment of wildfire debris flow potential
  3. AGU Day 4: Debris flows and the Station Fire [improved in light of comments from Susan Cannon]
  4. Mudslides occur in the areas affected by the 2009 Station Fire in Los Angeles