Perspectives Podcast Episode 29: Understanding flood risk

Jennifer Beaudry 
Welcome to Zurich Canada's Perspectives, where we stay connected with our partners and employees. We deliver market insights and thought leadership to bring information relevant to you, our listeners. I'm Jenn Beaudry, Head of Communications at Zurich Canada, and your host. Today I'm joined by Matt Rocha North America Lead Climate Change Resilience Services for a thoughtful conversation on the most common natural disaster in the country – floods. We’ll break down the real risk posed by severe weather and flooding in Canada, the different types of flood events, the common mistakes businesses make, what it means to build resiliency, and what businesses can do to help reduce flood risks. You won't want to miss this conversation. Matt, welcome. And thanks for joining us today.  

Matt Rocha 
Thanks, Jenn. Really excited to be here today. Thanks for the invite. 

Jennifer Beaudry 
Matt, we know flood events are becoming more frequent and more severe. Can you talk to us a little bit about the current risk landscape? 

Matt Rocha  
Foods are the most frequent and costliest natural disasters in Canada in terms of property damage. Last year, they caused roughly $1.5 billion in property damage across the country. And the insured damage from the 2021 BC floods was well over $500 million. We're inundated with an overwhelming amount of information every day. It's challenging for us to appreciate the devastation that these events can cause. I want to highlight the fact that once these events are off national news and social media we can under appreciate the devastation left. Some of these cities and towns and regions that have been impacted by these events are still feeling those effects today.

Jennifer Beaudry 
You mentioned the BC floods. We've already seen flooding events start to occur in BC this year and other parts of the country, as we approach flood season what are the key drivers of flood risk?

Matt Rocha
There's a variety of factors at play here. One of the big ones is our economy and our major city centres. We were established along the rivers – this is just how it worked. This was the mode of transportation to drive the economy back in the beginnings of Canada, and as these great cities, Toronto, Montreal, Vancouver developed, we just stayed where we were, and built and expanded outwards. So that flood risk that was always there is still present today. We've built public control mechanisms to try to mitigate some of these damages. But ultimately, the flood hazards still exist. We also can’t talk about floods without talking about climate change. You mentioned the BC floods last year – the increasing severity and frequency of events. These are becoming everyday news and we're seeing the effects of the wildfires going on. And in northern Alberta today, even right this week. I woke up this morning and two days ago there was yellow smoke in the Calgary region. We're living in this world of the changing climate. And so, as we can see, there's just so many factors that are tied to climate change, and how those strongly influenced the flood hazard level across the country. 

Jennifer Beaudry
We've seen an early start to the fire season in northern Alberta. Can you talk a little bit about how fires and forest fires in particular impact the flood risk?

Matt Rocha
Great question, Jenn. And so very important to know, as long after the wildfires have been extinguished, their effects are felt for years. And essentially, what's happened is we've lost the vegetation and the soils ability to absorb severe rain events. What this can lead to is increased potential for flash flooding following these events. If you are in regions that have been impacted by wildfire, your flood risk potentially has increased after that fire has been extinguished.

Jennifer Beaudry
So not all floods are the same. What are the different types of floods and how do they occur? You've kind of touched on it already.

Matt Rocha
We touched on a few. I'll outline four major flood types that we’re exposed to in Canada – fluvial floods or river or riverine floods when the water level exceeds the banks of the river that results in overland flooding in the surrounding regions. These can occur from large amounts of rain occurring upstream in the watersheds or from regional snowmelt. I live in Western Canada, we get a bunch of snow in the mountains when that snow melts, it increases the potential flood risk to Calgary. That's one of the drivers from the 2013 Calgary floods that resulted in roughly $2 billion in damage, which was the third costliest natural disaster in Canada, and the number one flood disaster. And because we live in Canada, we also love our cold winters. Now, what can happen with this is during spring break up, the ice can break up and it can create a blockage within that river, and you can actually have flooding occur upstream or behind the blockage. Now, when that blockage or dam releases, you can have a surge of water running down the river. And that can also then result in downstream flooding. And so, the important takeaway from ice chains is they're entirely unpredictable. They will follow some specific characteristics, but they generally are unpredictable. And they generally are not accounted for in flood maps, urban flooding or flash flooding. This occurs with those extreme rainfall events. And so this is the significant downpours that overwhelm the stormwater management systems are the public infrastructure that was originally designed to transport water to an area that won't inundate your property. Important takeaway here is that the public infrastructure in place generally has been designed to withstand less severe events. So more frequent events. Some of these rain events are the design details in these critical infrastructures might be designed to withstand a 10-year return period, or an event that has a 10% annual probability of occurrence. Now, if you have an extreme rainfall event, such as the atmospheric rivers we discussed earlier that impacted British Columbia, you know, these storms are what they refer to as 100-year storm, or potentially 100-year storm. And what that equates to is rather than a 10% annual probability of occurrence. Maybe that's a 1% annual probability of occurrence. So, what does that mean? It doesn't mean that this 100-year storm will happen once every 100 years, it means that 1% every year you have a 1% chance every year of being impacted by one of these events. An example of this was in 2013, and the downtown flooding in Toronto that resulted in roughly a billion dollars in damage. Lastly, we'll close out with coastal flood, tidal flood storm surge, you know, there's a lot of coastal regions in Canada. And as our friends in Greater Vancouver area will tell you, they experience high low tides twice a day, every day. And then when the moon is closest to the earth, they can also be affected by what they call king tides. And so this is extreme tide events where we can see an increased sea level rise within those coastal regions. Now, you can also be impacted by storm surge, which we experienced down in the East Coast last year during Hurricane Fiona, and are directly influenced by the atmospheric pressures and associated strong winds that come with these events. And so that puts our coastal cities and regions at risk during these these types of events.

Jennifer Beaudry
Now, turning to what you do every day at ZRS building resilience for businesses. What are some common mistakes businesses make when assessing flood risk?

Matt Rocha
Yeah, I think one of the biggest mistakes is underestimating your flood risk based on just understanding your hazard level. When you drop your PIN or your address or your location on a hazard map, and it returns that being a low hazard, that implies that you have a low flood risk. Now, as we talked about earlier, these hazard maps may not include all sources, they may only include riverine flooding, they may exclude urban flooding, and they may exclude ice champs. These are very tough to model and represent. And so, by just dropping a pin on a map does not equal a flood assessment, we need to consider all potential sources of damage. We need to consider what your local controls are. What you're doing both physically and operationally to reduce your risk. And then we also need to understand where your vulnerabilities are. For example, do you have your operations critical equipment located in a basement that could be exposed to flooding? There could be an example of being in a low riverine hazard area but having a high flood risk if an extreme rain event occurred, which resulted in flooding within your basement. Looking at all of these factors and understanding that when we look at these flood maps, they're just telling us one part of the story. And so just because you're outside of that blue boundary on a flood map, or it's right next to your property, that doesn't mean that's where the flood waters stop. These are not inundation maps, though, generally, when you're looking at these, these are hazard maps. And so that blue line doesn't represent where that water will stop, it's just meant to give you an indication. So you can have, you know, and plan for those appropriate operational and physical protection mechanisms, you may need to be resilient.

Jennifer Beaudry
You've talked about the planning a little bit, and you've talked about preparedness a little bit. Anything else you want to add about how businesses can better prepare themselves.

Matt Rocha
Number one is identification. We need to identify where these locations are, and in what proximity they are to the flood maps, as we mentioned, but also any other sources of flood damage. Is there a potential for ice champ? Is there a potential for atmospheric river and urban flooding within that region? Once we've identified then we can set up the steps to potentially mitigate. And once your property is built in these areas that could be impacted. It's not about picking your building up and moving it out of a flood zone. You know, this is not what we're expecting. We're just expecting that if you have vulnerabilities that you learn and can deal with those vulnerabilities. And so as I mentioned before, if you have operations, critical equipment in a basement level, is there an opportunity where that equipment could be relocated to above the basement level. So that could potentially eliminate one flood risk. And so in that mitigation, then allows you to prepare, right, and I'll use one example here from a client I visited in Calgary region a couple years back, prior to flood season, in their preparation phase, they deploy over two kilometers of temporary flood barriers. Every spring, this exercise takes weeks to accomplish, they have a team of people that go out and deploy this mobile flood protection. They deploy it in May. So, before the June flood season in Calgary, they leave the barriers up until mid-July, and then take them down after the flood season. It's not. This operation, like I mentioned, takes weeks to accomplish. And they need to be prepared for that. And also, to kind of close it out is they need to have an appropriate response. A flood response plan. What are you going to do to prepare before? What are you going to do to prepare during an event? And then how are you going to recover? As I mentioned before, some of these regional flood events can result in lasting impacts. It could take days or weeks for that flood water to recede. And how are you going to respond to that on your site. Ultimately, if there's been a regional flood that has impacted not only you, but the community as a whole, how are they going to respond? And how is your workforce going to respond and be able to come back and help you be resilient in your own operations?

Jennifer Beaudry
Thanks for taking the time to share these valuable insights with us, Matt, we really appreciate it.

Matt Rocha
Thanks for having me, Jenn, I look forward to our next discussion.

Jennifer Beaudry
Thank you for joining us today. To learn more about how to prepare for respond to and recover from flood related events, visit our flood resource hub on our website.