Why you should be aware of “burn scars”?

Extreme wildfire behavior is often devastating to both plant and wildlife. The landscape may look unrecognizable before and after a wildfire as swept through. During an active wildfire emergency, direct fire spread and assessing regional (if not national) health impacts from transported smoke plumes are often the immediate priorities being addressed. However, long after the wildfire has left the spotlight of the media, the story concerning wildfire impacts for that region are far from over!

I want to shed some light on a term you probably have heard on occasion, a “burn scar”. The term does a good job of describing what it is referring to. In extreme cases, it’s the visibly blacked out footprint left in the wake of a very hot wildfire that leaves hardly any trace at all of prior plant life. In such cases, even the root systems below ground could be charred! What I want to focus on, though, is the inherent flash flooding threat over and in proximity to burn scars!

It's not only the plant life that burns as a raging flame front crosses the land. Soils are adversely affected, too! Importantly, it’s possible for previously native soil being porous to suddenly become as effective as say asphalt for water infiltration purposes. Not good! Between a blackened near-impervious top soil and elimination of healthy vegetation that normally uptakes fallen precipitation, a scenario has been created that exacerbates precipitation runoff potential over the burn scar and into adjacent unburned lands. Should soil infiltration rates within and surrounding burn scars become exceeded by precipitation events, then flash flooding is more likely!

Another complicating factor enhancing the flash flooding risk is the influence of gravity on water runoff over steep, complex terrain, which usually is the typical background setting for frequent wildfires flaring up during the fire season over the Rocky Mountains of the western United States.

Burn scar flash flooding implications may even persist for years after the initial wildfire as the ecosystem takes time to heal. As a caution, it really is a good idea to be aware of any burn scars either where you live or outdoor recreate!

Photo Credit: Jonny William Malloy