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Sherburne County Multi -Hazard Mitigation Plan, 2020 and has a significant effect on its behavior. Temperature, humidity and wind affect the severity and duration of wildfires. Homes threatened by wildfire are primarily those located in the "wildland-urban interface." This is the zone where homes and subdivisions have been located in wildland areas where natural wildfires can have an impact. While wildfires are necessary for healthy ecosystems, they burn whatever fuel is in their path, whether vegetation or buildings. Because the severity of a wildfire directly impacts soil productivity and the vegetative recovery timeframe, the USDA Natural Resources Conservation Service (NRCS) classifies wildfires by burn severity to estimate soil heating and the severity of root damage. Wildfires are classified into one of three classifications based on post -fire vegetative and soil condition indicators. The most severe fires result in greatly reduced soil productivity, slow vegetative recovery (5-3.0 years) and great potential for soil erosion. Severe burning wildfires typically occurs in areas with steep north or east slopes and dense timber. On the opposite spectrum, the vegetation of an area impacted by a low -severity fire is likely to recover naturally, with regrow occurring within a year. Low -severity wildfires primarily occur on grasslands (USDA NRCS, n.d.). One of the most common causes of a home being damaged or destroyed is due to radiant heat. In a wildfire, radiant heat is the heat given off by burning vegetation. The high temperatures of some wildfires can cause the deck, siding, or roof of a home to ignite, because the fire was too nearthe home. Studies in western wildfires have shown that approximately 85% of homes surviving a major wildfire had 30-50 feet of defensible space around them, coupled with fire-resistant roofing. Approximately i,600 wildfires occurred each year in Minnesota on average from 3.976-2011 (MN DNR, 2011). Wildfires occurthroughout the spring, summer and fall, however, most wildfires in Minnesota take place in March, April, and May. During this period, much of the existing vegetation has been killed due to winter temperatures and is dead, brown and combustible. Also, there is little green vegetation to serve as a barrier for a moving wildfire. Wildland fire History in Sherburne County The Minnesota DNR responded to i,6i9 wildfires in Sherburne County from January 1985 throughJuly 25, 203.9, most being human caused, burning 8,964 acres (Figure 23). These include fires not only on state lands, but also rural private lands for which there is not another agency with primary responsibility. Wildfires that are not included in this data are those that occur on federal lands and those that are responded to by local fire departments. The largest wildfire in Sherburne County burned 2,50o acres in April of 1.996, northwest of Zimmerman. In April of 3.99o, a fire occurred west of Zimmerman, burning 688 acres. The most recent fire that burned more than ten acres in the county occurred in April of 2o3.8, burning 54 acres in the northwestern corner of the county. Its cause was arson. Only 20 wildfires in this dataset were ignited by natural causes (lightning), burning a total of nine acres. Page 181