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Sherburne County Multi -Hazard Mitigation Plan, 2020 According to MN DNR data, there are 23,418 acres of peat in Sherburne County. Peat is partially decayed plant matter found in ancient bogs and swamps. Minnesota has approximately six million acres of peatland, the highest total acreage in the contiguous United States. Peat fires are deep-rooted fires that burn underground, lasting for weeks, months, or even years. They can smolder during winter months beneath the snow, surfacing again in the spring to burn above ground. Peat ignites when its moisture content is low, and then it supports combustion rather than flame. Once started, combustion is persistent because peat contains oxygen and needs little or no outside oxygen to continue burning. Peat's insulating qualities mean the fire loses little heat. As the peat dries, it becomes water repellent. These factors result in long-lasting fires that require extensive operations to extinguish. However, peat fires have not been an issue in Sherburne County. To determine the probability of future wildfire events in Sherburne County, all past -observed wildfire events and the period in which they occurred were examined. Based on Minnesota DNR records from January 1985 through July 25, 2019, the relative frequency of wildfire events in the County is 47 events per year. This relative frequency can be used to inferthe probability of these events occurring in the future. Wildland fire and Climate Change Temperatures are predicted to rise in the state, which could lead to more extreme heat events and associated wildland fire risks. As Minnesota's climate changes, weather fluctuations between drought and extreme rain events and increasing temperatures will result in changes to forest composition and/or distribution. These fluctuations can lead to dry conditions that may cause increased fire risk in both grassland and forest environments. Vulnerability Wildland fires occur frequently in Sherburne County, with larger ones tending to happen within the Sherburne National Wildlife Refuge. Some residents are more vulnerable to air quality conditions of wildland fire and those include children, older adults, and those with respiratory issues. The Household Composition & Disability SVI theme map (section 3.6.3.) is made up of these population groups and should be reviewed to better understand the vulnerability of each jurisdiction. The SILVIS Lab at University of Wisconsin — Madison created a nationwide dataset documenting the 203.0 Wildland Urban Interface. With the increase of development in metropolitan fringes and rural areas, the wildland-urban interface (WUI) is increasing. The WUI is defined as the area where structures and other human development meet or intermingle with undeveloped wildland. The expansion of the WUI in recent decades has significant implications for wildfire management and impact. The WUI creates an environment in which fire can readily move between structural and vegetation fuels. Its expansion has increased the likelihood that wildfires will threaten structures and people. There are two types of WUI: intermix and interface. Intermix WUI are areas where housing and vegetation intermingle; interface WUI are areas with housing in the vicinity of contiguous wildland Page182