We have just survived what was probably a 1000 year event in central Colorado – a week of torrential rain that has left the Front Range in a shambles.
This isn’t the first time that the Front Range has flooded. In the twentieth century alone, we had four monster floods: Pueblo, 1921; Denver, 1965; Big Thompson, 1976; and Fort Collins, 1997. But this storm dwarfed the others, both in area and in duration. The twentieth century storms were preceded by a few days of rain, then a triggered by a localized thunderstorm. The 2013 Week of Water had days of heavy rain from New Mexico to Wyoming, followed by God’s faucet being left on over Boulder and Aurora. (Colorado flooding 2013: Map of rain totals http://www.denverpost.com/2013coloradofloods/ci_24101329/colorado-flooding-2013-precipitation-totals) These areas received a year’s worth of water in a week, leaving Lyons, Jamestown and other communities devastated. The rest of the Front Range got inches to half a foot and dealing with leaking roofs and flooding basements.
The characteristic that made this storm so unusual was that it stalled above us, and pumped in unbelievable amounts of water from the Gulf of Mexico. (Colorado Deluge: “Could Be Classified as a 1,000-Year Event”)
We’re going to be rebuilding for a long time. A very nice editorial from the secretary of Vermont Agency of Natural Resources published on CNN (What We Learned From Vermont’s Epic Flood http://www.cnn.com/2013/09/16/opinion/markowitz-colorado-floods-vermont-irene/index.html?hpt=hp_bn7 suggests that we rebuild with a view to durability – how do we build to avoid being washed away again.
Because, even if this was a 1000 year event, consider this: Just because we’ve had a 1000 year event doesn’t mean that we’re safe for the next 999 years. The way statistics works, we could have another one next year or next month.
And that’s not including that the climate models suggest that with global climate change, the climate will become more erratic — deeper droughts punctuated by big storms. Storms like this one.