Heavy Flagstaff Flooding Possible from High Severity Fire in Watershed

Aug 1, 2019

Coconino County emergency managers are anticipating heavy flooding in some parts of Flagstaff following the Museum Fire. KNAU’s Ryan Heinsius reports, much of the watershed in east Flagstaff burned significantly, which makes it susceptible to flooding during the monsoon.

Coconino County Flood Control District Administrator Lucinda Andreani stands next to some of the many concrete barriers put up on Paradise Road where some of the heaviest flooding from the Museum Fire is possible.
Credit Ryan Heinsius / KNAU

Forest and county officials are analyzing the burn severity of the 2,000-acre Museum Fire to try to predict flooding impacts. Even through a majority of the fire burned at either low or very low intensity, more than half of the watershed above several neighborhoods received moderate or heavy fire. That has county managers worried monsoon rain won’t be absorbed into the ground and will flow into residential and business areas.

"The soils really are fried … They’re like a sheet of glass. So if you took a sheet of glass and you poured water on it what happens? It just pours off. So 52% of the watershed has soils that are like a sheet of glass, likely," says Coconino County flood control district administrator Lucinda Andreani.

Andreani says 3,000 cubic feet per second of water—or about a third of the Colorado River’s average flow—could potentially rush into some neighborhoods after a heavy rainstorm.

So far, crews have placed a million-and-a-half sandbags near homes at Mount Elden along with five miles of barriers. In east Flagstaff, 600,000 sandbags have gone in.