New Mexico Scientists Predict Wildfire Erosion Risks

It’s nearly impossible to predict when and where the next major wildfire will be and whether an ill-timed thunderstorm could result in tons of ash and charred debris being washed down the bare mountainsides once the flames are out.

But scientists working in New Mexico have developed a new method for sizing up which chunks of overgrown forest are most at risk of burning and sending waves of debris toward communities and into key areas that provide sources of drinking water.

The research by the U.S. Geological Survey and The Nature Conservancy focuses on a pair of mountain ranges bordering New Mexico’s most populated area, but the scientists said their method can be applied to landscapes around the West.

“It takes it up a notch,” Anne Tillery, a USGS scientist in Albuquerque, said of land managers’ ability to make predictions with the new method.

The work by Tillery and her colleagues marks the first time scientists have brought together various computer modeling tools for predicting burn probabilities and fire behavior. They combined that with surveys calculating the steepness of the terrain and the density of pinon, juniper and other trees throughout the Sandia and Manzano mountains to get a good idea of what might make for post-fire flooding hotspots.

The research began in 2013. Details of the work are outlined in a study released this week.

The scientists say they have plans to use the method in the Jemez and Sangre de Cristo mountain ranges in northern New Mexico. “As we continue to do these types of studies, we’ll refine the methods. But I think it’s really a big step,” Tillery said.

Like Arizona, Colorado and other Western states, New Mexico has had back-to-back record wildfire seasons within the last few years. In 2011 and 2012 alone, thousands of square miles were burned in New Mexico, and communities around the state are still living with the consequences of flash flooding during the monsoon season.

The study said erosion caused by the flow of debris and flash floods can be the most catastrophic of post-fire threats.

Special teams typically respond following large wildfires to assess what damage might come following the flames. But the new research is aimed at making changes on the front end, said Laura McCarthy of The Nature Conservancy.

With federal funds tight for forest-restoration efforts, McCarthy said the new tool will allow land managers to specifically target those areas that have the highest risk of flooding and debris flows.

“Figuring out which areas are vulnerable to damaging wildfire and post-fire flooding is necessary to protect communities and our water sources,” McCarthy said.