It Feels Like 10 Big Thompson Floods All Happened At Once
The floods of September 2013 have left a lot of people at a loss for words or even ideas. Some, but not all, of the TV coverage consists of disconnected montages of video clips lacking context and connective threads. Having worked at the State of Colorado’s floodplain management program for more than 25 years, I’m experiencing a different problem: too many words, too many ideas, too much context and too many connective threads. Can’t process it or turn the brain off. Nevertheless, it’s tough to pull all the pieces together
On July 31, 1976, I went camping at the Mountain of the Holy Cross (near Minturn) with friends. Five minutes after we climbed into our tents, rain & lightning like I had never experienced kept all of us awake & trapped in our tents. Meanwhile, about 60 air miles to the northeast, the Big Thompson Canyon was coming unraveled.
When I began my state floodplain management job, the Big Thompson was our frame of reference for flood disasters in the Front Range foothills. Not surprising, given the large loss of life (139). Now we have a new set of lessons to process.
The storm I experienced in Eagle County was only loosely related to the Big Thompson storm. The 1976 flood disaster resulted from a localized thunderstorm that got stuck on the Continental Divide above Estes Park and poured over 10 inches in about four hours. The 2013 flooding resulted from heavy rains that lasted about 48 hours, with less heavy rains occurring before and after that intense 48-hour portion of the storm. The 2013 rains extended essentially from Wyoming to Monument Ridge and from a little east of I-25 to the Continental Divide. From the Cache la Poudre to Bear Creek and beyond, multiple canyons small, medium, and large each seemed to have their own Big Thompson flood all at the same time. The 2013 version was far longer-lasting in time and much, much larger in geographic extent. The sum of all those individual disasters flowing into the South Platte is still part of the 5:00 news as I write this on September 19, taking its time and doing great harm on its way to Nebraska. To cap off the anomalies, it happened in September, not in July or August, the historic monsoon period in the Rockies.
What about flooding in Greater Park Hill? Three watersheds in east Denver were affected. Stubborn cells along I-225 poured rain on Westerly Creek and, to a lesser degree, on Montclair Creek and “Park Hill Creek.” Working at my son’s house in East Montclair most of Thursday, September 12, to keep water flowing away from his basement, I watched Montclair Creek go up, down, up, down multiple times. It’s been higher in the past, but I’ve never seen it stay high for such a long time. Between Lowry and Stapleton, residents along Westerly Creek (11th to Colfax, Verbena Street to Yosemite Street) were evacuated on Thursday afternoon, for fear of a dam failure at Kelly Road Dam at 11th and Willow, with water flowing over the dam’s spillway. Not much problem beyond a little high water on Park Hill Creek. The map below shows the watersheds and an estimate of the 48-hour rainfall they experienced. We got off lightly!
Brian Hyde can be reached at westerly_connect_brian@comcast.net.