How to plan for summer floods in Canada

As extreme rainfalls become more frequent and costly, old infrastructure cannot keep up
Tuesday, July 19, 2016
By Stephen Gill

With each summer storm season instances of flooding become more frequent and costly. Almost a month after Calgary marked the three-year anniversary of its devastating 2013 floods, torrential downpours hit the city last week on July 15. Basements were flooded, streets and sidewalks became rivers and buildings were left in disarray. Currently, the city has already doubled its average rainfall for this whole month.

Flooding, which is also happening in different pockets across Canada, occurs after several days of prolonged rainfall, short periods of intense rainfall or when ice or debris jams and causes a river or stream to overflow. The result can quickly move from saturated ground to a catastrophic situation. As it stands, the impact of climate change is increasing the occurrences of extreme rainfalls and old infrastructure, such as sewers, cannot keep up.

The way to best protect properties is to develop and follow a well-thought out disaster plan, customized to the facility’s location. These action steps include pre-flood, during flooding and post-flood. While a plan can be designed according to a specific property in jeopardy, there are basic steps a facility manager or contractor can follow when responding to diverse flooding activity and while flood waters quickly escalate, move and rise.


  • Be alert to the possibility of a flood and know that this is the time to initiate a disaster plan.
  • Post all notices of expectations and efforts in a place for all tenants or community members.
  • Keep track of your local weather updates as they provide the best advice for your situation.
  • Be aware of distant events, such as dam breaks or thunderstorms resulting in area flash floods.
  • Assemble all flood supplies well in advance according to your need and location.
  • Prepare for worse-case scenario: Fill any receptacle with clean water, as a backup. House all outdoor belongings inside. Move any relevant office equipment to the highest level in your building for water damage protection. Take special care in determining and moving any toxic or flammable containers to eliminate hazardous explosions or leakage.
  • Gas all company vehicles for emergency purposes and know clear and safe evacuation routes.

As flooding occurs

  • Shore up the building contents: If the storm is eminent and you know your facility is at risk, round up valuable items or documents and store them in a secure and dry location. Clean out gutters and downspouts and ensure your sump pump is working.
  • Power: Follow authorities’ guidelines when asked to turn off all utilities at the main power switch and close the main gas valves to avoid further damage to your properties and surrounding communities. Often power is restored without notice, which could present a shock hazard to anyone in the area
  • Structural: When you enter your damaged building, be aware of its structural integrity and other potential hazards, such as falling debris. Stay out of the floodwaters as much as you can to avoid the risk of injury. Also make sure you’re wearing the right personal protective equipment—protective clothing, sturdy shoes, gloves, eye protection and a paint respirator can help protect you from microorganisms that grow quickly after floods.


  • Clean quickly: Control or minimize the speed of mould growth by keeping air moving through the space with open windows and doors. Mould thrives in moist environments (particularly ones with stale air, food sources like paper and wood, and temperatures between 20- and 30-degrees Celsius), so maintain a steady supply of fresh air. This discourages the growth of mould and other microorganisms and also helps guard against inhalation risks.
  • Be thorough: Remove and dispose of anything wet and porous, such as mattresses, moulding, insulation and damaged portions of walls. Floor coverings like carpet, pads, laminate, tile and sheet vinyl must also be disposed of. Wood flooring should be removed so you can expose, dry and clean wet saturation pockets underneath. You’ll also need to disinfect structural areas, such as wall cavities, studs and other fixtures. This can be done by pressure washing with detergent solutions from top to bottom.
  • Dry everything: After disinfecting, the entire space needs to dry thoroughly before you can begin reconstruction. Surfaces may feel dry to the touch, but that doesn’t mean they are truly dry. If you start reconstruction too early, you may end up with dry rot, ongoing structural damage or adverse effects on human health. Consider a professional moisture assessment to make sure it’s safe to proceed.
  • Repeat Safety Walk: Walk through all building areas several days in a row after the flooding has subsided to determine if there are any structural or personal changes that could be harmful.


Stephen Gill is the directing partner of Flood Risk Canada where he leads the Emergency Flood Risk Team throughout the U.S. and Canada. For more than 20 years, he has consulted with facility managers, building contractors, property managers, lenders and insurance brokers/carriers. Flood Risk Canada is strong in complex flood-modeling and impact studies due to climate change. The organization’s efforts are focused to clarify key guidelines for flood exposure. Stephen can be reached at sgill@floodriskcanada.ca or 647-497-8257.

“Are you interested in knowing further about your Flood Zone?  Let’s determine that. We are happy to do an initial determination, free of charge.”


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