In September of 2013 one of the worst floods in Colorado history hit the Front Range region with devastating force. Caused by the clash between a slow-moving cold front and warm humid monsoonal air from the South, the subsequent flooding led then President Barack Obama to declare a state of emergency in the area. Boulder County (home of Map Mavin) was the worst hit, receiving 9 inches of rain on September 12th and 17 inches on September 15th. To put these figures in perspective, Boulder’s average precipitation for an entire year is 20 inches.
Using Map Mavin, I was able to easily create a map that would help the average person make sense of the true extent of the floods. Flood data is often easily retrievable online as government agencies tend to publish many of their findings and datasets on their sites, especially if the natural disaster in question was catastrophic in scale. In the case of the 2013 Front Range floods, I was able to find shapefiles showing flood extent on the city websites of several Colorado communities. Seeing that Boulder was the worst hit and that we are based here, I chose to use it as our area of focus (in fact, our office building was within 200 feet of the flood path!).
First, I made sure to include in my web map a layer of all streams, creeks, reservoirs and lakes in Boulder. This layer, which you may have encountered in earlier maps I’ve shared, is also available on the City of Boulder’s website. Second, I added the 2013 Boulder Flood layer that I’d downloaded from the same site.
Next, I made sure to set the extent of my web map to hover over central Boulder. Lastly, I went to the settings page of the 2013 Boulder flood layer and changed the opacity level to 50% so that the original creek paths would shine through. In doing this, users are able to see just how far out the flood spread from the normal water paths in town.
And that’s it! What may look like a complicated project at first glance in reality only took me about five minutes to put together.