Wildfires then landslides, a sadly predictable pattern

The devastation in BC, Canada seems non-stop this year. After drought and high temperatures led to a deadly fire season, those wildfires have led to severe flooding and landslides. Imagine having all four major highways that connect a major metropolitan area cut off in one event. It makes me think of disaster movies that I watched for the excitement and really bad science that you always thought were too far-fetched to have any connection to reality.

We know that climate change is leading to more frequent extreme weather events. But what is rarely discussed, at least until now, is how more frequent extreme weather events also contribute to more frequent extreme weather events. Fires leading to landslides is the most common. But why is the connection so strong?

Fires destroy vegetation. That’s pretty obvious. But part of what gets destroyed are the root structures. As we see every time someone decides to cut down trees to open up their view of something like a river valley, the roots are what hold the soil together. Without them, it is much easier for water to pick up the soil and continue to move. This is why flooding and landslides often follow major fires.

In BC’s case this year there was an added issue. They had already had a wet fall. Just like a sponge that has to be wrung out before it can absorb more water, the soil was already saturated or at least close to it. In other words, the soil couldn’t absorb any more water. So, when an atmospheric river, basically a water system carrying a river’s worth of water, poured down on the same land that was burned earlier in the year, and then was already hit by heavy rain, it was unstoppable.

The thing is that because of climate change, weather is changing faster than we can adapt. Our infrastructure and our predictive models aren’t prepared for the changes. But we do know what needs to be done for climate change. We have to decarbonize. The costs of not doing so are, as we’re seeing in BC, life threatening.