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Memories of disasters are all too soon forgotten

From Ripple Effect, a weekly newsletter from The Red River Basin Commission

With the recent spate of wet years here in the Red River Basin, we’ve heard more than usual about risks of flooding. Statistical risks for flooding are based on the historical record of flooding and are typically expressed as statistical chances for certain levels of flooding in any one year.

For example, there is a one per cent for a 100-year flood in any single year, a .50 per cent for a 200-year flood, a .20 per cent chance for a 500-year flood.

But is this the way most people think of the risk of flooding? Research by Nobel Prize winner in economics, Daniel Kahneman, about how people think when it comes to risk suggests the answer is no.

What do we know about how we think of risk? First, we know people are most diligent in responding to risk right after they have been affected. For instance, after major earthquakes in California, citizens become more diligent about purchasing insurance and practising other measures to protect their lives and property. After some time elapses, however, memories dim and these actions drop off, even though actual risk for earthquake damage hasn’t changed.

Why does this happen? Kahneman concludes that this typical response to risk has much to do with our short memories when it comes to risk situations. It is this out-of-sight, out-of-mind, thinking that results in the typical cycle of “disaster, concern and growing complacency” that is all too familiar to those in emergency work. An example of this cycle hit close to home in 2011 when Minot, North Dakota, which had not experienced flooding for many years, was caught unprepared, the city and its individual property owners alike.

A second thing we know about how we think of and respond to risk is that we tend to assume that the level of risk ahead will only be as great as the worst disaster we have already experienced. Kahneman notes that as far back as ancient Egypt, high water marks were recorded with each flood and used to determine the preparation level for the next flood. This practice continues in many instances even today.

Here in the Red River basin, for example, much of the planning for future floods is still aimed at the more familiar floods of 100-year magnitude or smaller, even though several areas of the basin have already experienced flooding up to 200-year and even 500-year levels.

Why do we have trouble preparing for potentially larger floods? Kahneman’s answer is that we’re being tricked by our imaginations. Most of us, he explains, have trouble picturing risks we haven’t seen, whether they are earthquakes or floods. As a result, we continue to think in terms of what we have available in our minds.

Yes, here in the Red River basin, we’ve experienced much flooding, and we’ve been informed that greater floods are possible. But we’ve had a dry fall, and winter thus far has produced little snow. So what are our minds telling us today about flood risk?



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