Wildfires have affected the county , but the most destructive to the townsite was the Cerro Grande Fire of May 2000 , which caused an estimated $ 1 billion in damages and destroyed more than 400 homes . The fire was supposed to be a controlled fire to try and prevent a wild fire . They intended to only burn 900 acres , but things got out of control and more than 1,000 firefighters were on scene . which resulted in 48,000 acres burned . The town was evacuated for eight days . The Federal Emergency Management Agency ( FEMA ) built temporary housing on North Mesa for those who were displaced by the fire . Though there was no loss of life , other effects include damage to LANL facilities ( nuclear material was not affected ) , flash-flooding , and erosion . The Las Conchas Fire of June 26 , 2011 burned about three times as many acres and also prompted evacuation of Los Alamos , but there was no damage to property in Los Alamos.It was the biggest wildfire New Mexico had endured . Wildfires have altered plant communities in the area . Plant species are migrating to cover burn areas
Las Conchas Fire
Las Conchas Fire
Los Alamos, New Mexico