NEW MEXICO (KRQE) – With the recent wildfires and severe flooding in New Mexico, the connection between the two natural disasters has been apparent due to the long-lasting and immediate impacts of burn scars. In June, Ruidoso and the surrounding areas experienced two major wildfires, followed by flash floods from rain that fell on the fresh burn scars. As that was taking place, the City of Las Vegas also experienced severe flooding from a downpour on the 2-year-old Hermit's Peak/Calf Canyon Fire burn scar. Largest wildfires in New Mexico history Looking back at New Mexico's history of wildfires, which is partially displayed on the map below, you'll see that the number of fires and burn scars that were left behind from 1911 to 2017 is significant. Wildfires in New Mexico from 1911 to 2017. (Data from UNMRGIS) Calf Canyon Hermits Peak Fire map, Sept. 18, 2024. (Credit: Southwest Area Incident Management Team) The map above does not feature the largest fire in New Mexico state history, the Hermit's Peak/Calf Canyon Fire, which burned more than 340,000 acres starting in April 2022, and the second largest fire, the Black Fire, which charred more than 325,000 acres in May that same year. To understand the impact of burn scars, KRQE News 13 spoke with State Forester Laura McCarthy. Below, you will find a series of questions and answers from the conversation. **Editor's note: Some of McCarthy's responses below have been shortened for clarity purposes. What is a burn scar? McCarthy: "A burn scar is the area that a wildfire moved through, and we generally think of burn scars as having different levels of severity of burn, ranging from very little impact of a low ground fire, a low severity burn, to a high severity burn where everything can be gone, all living vegetation, and sometimes up to a foot or two of ash." How do burn scars impact the ground and plant growth? McCarthy: "So it really depends on the severity of the burn. So in a low severity burn, you can sometimes see that the flames have licked around the bases of, say, larger ponderosa pines, and you might see some scorch marks on the trees, and you might see some brown needles up above in the tree canopy, and you would probably see very patchy, what's called leaf litter, so the debris that was on the ground—some of it might be burned all the way through, some of it not. That's the one end of the extreme, the low severity." McCarthy: "On the high severity, where you have a foot or two of ash, there is really nothing left. You might even see places where there were tree roots, and the roots themselves burned hot, and you'll see these sort of interesting depressions in the ground where the tree roots got burned out and just completely vaporized." Can you replant in a burn scar area? McCarthy: "In the areas of high severity burn, you really need to give it some time for the ash and debris to move, and it is rain that's going to make it move. It's also true that depending on the timing of rainfall, you might have a pretty good flush of green vegetation, grasses, and other forbs that will come up even in the first growing season. We saw that in the Hermit's Peak Calf Canyon Fire footprint, because the monsoon rains did come shortly after that fire, and in early September, there was greenery. And what that means is that the trajectory of recovery of every burn scar is going to be different based on the proportion of low, medium, and high severity acres, and the timing of rainfall." The NMSU Forest Research Center and Nature Conservancy are working to grow Ponderosa Pine seedlings to plant in the burn scars of the Jemez Mountains, left behind by the 2011 Las Conchas fire. McCarthy: "Replanting in burn scars is very important, and it is a priority for the state to make sure that we have the tree seedling resources to do the right kind of replanting that will be successful because a burn scar is a very harsh environment. We also can't replant too soon." McCarthy: "Depending on the intensity of the rainfall and the frequency, it can be up to seven to ten years until the ground is stabilized enough to make it worth replanting." An example of replanting trees in the Las Conchas burn scar can be found in KRQE's past coverage here. Can you rebuild on top of a burn scar? McCarthy: "So the actual building process is not my expertise. I think that when homes are lost in wildfires, it does create a really difficult situation for the property owner. And there are some places where rebuilding would absolutely make sense, and there are other times and circumstances where a property owner might need to look at that fairly carefully." How do burn scars contribute to large floods? McCarthy: "Initially, the first rainfall, the raindrops are going to encounter a surface that is water repellent. Then the drops are going to start to roll downhill, and they're going to pick up momentum, and pick up debris, and ash, and start to spiral down and become an actual flow that often happens. Over time, the rain is going to erode into the ash." Ruidoso flooding | Courtesy: Jesus Figueroa McCarthy: "I think something that people don't think about much or appreciate until it's gone is how forests are actually functioning like a sponge to rain. That when it rains in an unburned forest, first you have the tree canopy, kind of breaking the impact of the raindrops, and then dripping off of the trees." McCarthy: "And the water gets absorbed. It percolates down through the soil until it hits bedrock, and then it's going to flow underground into our streams as beautiful, clear water. All of that's now gone in a high-severity burn scar. And that's why we end up with that pretty icky, black water running rampant." Can wildfires re-burn a burn scar? Las Conchas fire 2011. (KRQE) McCarthy: "Typically, a re-burn that happens at about 15 to 20 years later can be really destructive, and that's because there's enough vegetation in what was the burn scar that it will burn hot, and it can burn so hot that it consumes everything. We've seen that in Las Conchas. A significant portion of the Las Conchas fire (2011) was in a 1996 burn scar, and it was very destructive there." McCarthy: "On the other hand, if, say, the weather hadn't changed in the case of the South Fork and Salt fires (2024), and if one of those two fires had burned into the McBride area (2022), that would have only been two years since that fire had happened, and I believe it would have acted as a buffer and a safe place for firefighters to be able to catch the fire as it came in." Is there anything else important to know about burn scars? McCarthy: "There are some things that people should be thinking about in regards to burn scars, especially new burn scars, and that is how the debris flow and flooding can be life-threatening.  McCarthy: "There is a very good free app called 'Watch Duty' that people can download to stay informed and get local updates from the community emergency managers so that they can stay alert." McCarthy: "If you see flooding or if you see a scary black cloud over a burn scar, get to higher ground.  Don't take chances. If you're on a back road, turn around and get yourself to higher ground."