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Designing for Hazards – A Wall of Lake Ice

Who is responsible for determining the impact and designing to protect against manmade or natural disasters on your home or neighborhood?

A local state of emergency has been declared in a western Manitoba municipality after homes in Ochre Beach were destroyed and seriously damaged by a wave of lake ice.

Area officials told CBC News the wind pushed built-up ice off Dauphin Lake on Friday evening and caused it to pile up in the community, located on the lake's southern shore.

The piles of ice, which were more than nine metres tall in some cases, destroyed at least six homes and cottages, according to the Rural Municipality of Ochre River.

Via: Wall of ice destroys Manitoba homes, cottages – Manitoba – CBC News

Depending on the hazard, different jurisdictions deal with the issue of responsbility differently. Here's some examples when it comes to development and evaluating hazards (note that there is extensive legislation outlining the responsibilities, this is intended only as a snapshot, not as a guide):

  • In British Columbia, it is common practice for proposed subdivisions in steep and hazardous terrain to be required to undertake slope stability assessments. The areas are defined by local governments, but the assessment is the responsibility of the developer's consulting engineer. See Seismic Slope Stability Requirements in BC — UrbanWorkbench.
  • In Australia, bushfire risk assessment and mitigation is the responsibility of the developer's consultant working in conjunction with the local government – see FPA Australia | Bushfire Consultants.
  • In British Columbia, flood hazard assessment is a multi-jurisdictional responsibility. Lands that may be subject to flooding are identified and rules for development are embeded in the local government's Official Community Plan, but more broadly, flood protection is a provincial responsibility. Meeting those rules, which may include minimum building elevation, emergency access elevations, or other mitigating measures, is the responsibiilty of the developer's engineer.

So who is responsible for mitigating the risk of a 9m high wave of ice blown off the lake in May? Was it even considered when the development was approved?

 

Mike Thomas

Mike Thomas P.Eng. ENV SP, is the author of UrbanWorkbench.com and Director of Engineering at the City of Revelstoke in the Interior of British Columbia, Canada. If I post something here that you find helpful as you navigate the world of engineering, planning and building communities, that’s wonderful. But when push comes to shove: This is my personal blog. The views expressed on these pages are mine alone and not those of my employer.

3 thoughts on “Designing for Hazards – A Wall of Lake Ice

  1. Another example of designing for natural disasters was recently reported in BC, in this case, the engineers were warning the client, but it seems they were being ignored!

    On Dec. 19, 2013, several weeks after the bridge opened, heavy shards of ice and snow — dubbed “ice bombs” by some — fell from bridge cables causing damage to over 300 vehicles and shutting the toll bridge for four hours.

    Documents obtained by Global show that when bridge designers responded to specific questions about whether measures had been taken to ensure that snow and ice would not fall onto cars, design review engineers were apparently not pleased with the answers. One 2009 document shows an engineer’s handwritten note, that says “but that could still fall onto traffic!”

  2. As soon as I saw the Port Mann being built even I could see that there might be problems with the suspension cables meeting over the roadway.
    One of my philosphies is “What if?”
    e.g. Further along the road where I live I notice that above some buildings there are some large rocks in the Kame terrace that look as though they will fall down some day. I have live here for some fourreen years now and nothing has happened. But some day. . . . I feel that I should ask the city council if they are aware of the situation. I will do that today.

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