A Perspective on Front Range Floods

John Pitlick
			
The hazards associated with rare but intense rainfall are well known in Colorado, and many 
communities along the Front Range have taken action over the years to mitigate potential 
damage and loss of life from rare floods.  Last week we had the opportunity to observe first 
hand what it is like to get half a years-worth of precipitation in one or two days, and we 
can begin to appreciate how the actions taken to reduce flood risks in Boulder benefited the 
community as a whole.  Nonetheless, throughout Boulder, streets and alleys become torrents, 
carrying mud and rocks indiscriminately into homes and businesses.  Residents in mountain 
towns and outlying areas have been isolated by road washouts and bridge failures.  Certainly 
many questions will arise in the aftermath of the 2013 flood.  For example, newspapers are 
reporting that this was a 100-yr flood.  What is the basis for that estimate?  How do 
published maps of inundation for floods with different return periods compare with the 
extent of flooding in 2013?  Did burned areas contribute disproportionately to the floods?  
I don’t have complete answers to these questions, but I am happy to share results from past 
work (my own plus others) that helps put the 2013 Boulder Creek flood in perspective.