SANTA FE, NM – Sept. 24, 2020 – The Forest Service Burned Area Emergency Response (BAER) Team assigned to the Medio Fire on the Santa Fe National Fire (SFNF) completed a rapid assessment of the fire’s effects, including the potential for post-fire flooding, erosion and sedimentation. The BAER Team’s primary focus was on immediate risks to human life and safety.
The team used satellite imagery to map the burn severity of the approximately 4,000-acre Medio Fire. Nearly half of the fire’s acreage – approximately 49% – burned at low severity, with 16% at high severity and 14% at moderate severity. The remaining 21% of the footprint, including 24 acres of rock outcrop, was unburned.
Since the lightning-caused Medio Fire occurred after the SFNF’s typical spring fire season, “the probability of the monsoonal rainfall that usually causes the most severe post-fire flooding is much lower,” Acting Forest Supervisor Debbie Cress said. “Based on the BAER Team’s analysis, we are anticipating minimal immediate effects from the fire. Once the snow melts next spring, we have the option to initiate a second phase of BAER analysis to take a look at additional critical values above and beyond our current concerns for life and safety.”
The fire’s most immediate impact is the continued closure of the Medio Fire area, roughly defined by the Rio Nambe Trail #160 on the north, the Borrego Trail #150 and Forest Road 412 on the east, Forest Road 102 on the south and back up the forest boundary line on the west to meet the Rio Nambe Trail #160. The closure area includes the entirety of the Rio en Medio Trail #163. Trails in the high-severity burned areas were impacted by the fire, and the area is unsafe for public entry.
The BAER Team’s runoff analysis indicates that approximately 1,187 acres, 30% of the fire area, has high potential for post-fire runoff. Preliminary estimates indicate that a typical summer thunderstorm over this area after the Medio Fire would produce a peak flow five times greater than the same amount of rain prior to the fire.
But even at peak flow, runoff from the Medio Fire is unlikely to reach levels seen after the 2011 Pacheco Fire. Only about 8% of the Rio Nambe Reservoir Watershed is within the Medio Fire perimeter, and less than half of that area burned at the high or moderate severity that can result in post-fire runoff into Nambe Reservoir. In 2011, the Pacheco Fire impacted about 60% of the Rio Nambe Reservoir Watershed with more than half of that area mapped as moderate or high burn severity. The number of acres that contributed to high runoff and sediment and debris flow to Nambe Reservoir after the Pacheco Fire was 10 times the number of acres with similar potential after the Medio Fire. The Pacheco Fire also occurred just prior to the monsoon season.
Although the SFNF does not usually see monsoonal-type precipitation in September, residents of communities downstream from the burned area are advised to stay updated on weather conditions that could result in heavy rains over the Medio Fire footprint. Current weather and emergency notifications can be found on the National Weather Service website and through Alert Santa Fe.
The BAER Team’s findings will be shared with the National Weather Service, the US Geological Survey, interagency cooperators, tribal partners, state and local governments, and downstream communities to help them prepare for post-fire impacts.