Hazard Mitigation Plan Washburn County, Wisconsin Original Plan Date – August 2010 EPTEC, INC Lenora Borchardt 7027 Fawn Lane Sun Prairie, WI 53590-9455 608-834-0802 [email protected] Contents Table of Contents Table of Contents ............................................................................................................ 3 Introduction and Background .......................................................................................... 6 Previous Planning Efforts and Legal Basis ........................................................... 7 Plan Preparation, Adoption and Maintenance ...................................................... 9 Physical Characteristics of Washburn County ............................................................... 12 General Community Introduction ........................................................................ 12 Plan Area ............................................................................................................ 14 Geology .............................................................................................................. 15 Topography ........................................................................................................ 15 Climate ............................................................................................................... 16 Hydrology ........................................................................................................... 19 Soil Types ........................................................................................................... 21 Wetlands ............................................................................................................ 23 Land Use ............................................................................................................ 25 Vegetation .......................................................................................................... 28 Demographics ............................................................................................................... 29 Human Settlement Patterns................................................................................ 29 Population .......................................................................................................... 30 Transportation Network ...................................................................................... 32 Washburn County Roadway Classification ......................................................... 32 Classification ................................................................................................................. 32 Public Safety Support ......................................................................................... 33 Archaeological and Historical Resources ........................................................... 38 Hazard Analysis ............................................................................................................ 44 All Hazards .................................................................................................................... 46 Vulnerability ........................................................................................................ 46 Hazard Mitigation Strategies............................................................................... 47 Drought and Dust Storms .............................................................................................. 52 Physical Characteristics ..................................................................................... 52 Frequency of Occurrence ................................................................................... 54 Vulnerability ........................................................................................................ 55 Hazard Mitigation Strategies............................................................................... 55 Earthquakes .................................................................................................................. 57 Physical Characteristics ..................................................................................... 57 Frequency of Occurrence ................................................................................... 59 Vulnerability ........................................................................................................ 62 Hazard Mitigation Strategies............................................................................... 62 Flooding and Dam Failure ............................................................................................. 63 Physical Characteristics ..................................................................................... 63 Watersheds ........................................................................................................ 67 Floodplain Regulations ....................................................................................... 71 Frequency of Occurrence ................................................................................... 72 Vulnerability ........................................................................................................ 73 Page 3 Contents Hazard Mitigation Strategies............................................................................... 75 Forest and Wildfires ...................................................................................................... 80 Physical Characteristics ..................................................................................... 80 Frequency of Occurrence ................................................................................... 82 Vulnerability ........................................................................................................ 82 Hazard Mitigation Strategies............................................................................... 82 Landslide ....................................................................................................................... 85 Physical Characteristics ..................................................................................... 85 Frequency of Occurrence ................................................................................... 87 Vulnerability ........................................................................................................ 88 Hazard Mitigation Strategies............................................................................... 88 Severe Temperatures .................................................................................................... 89 Characteristics .................................................................................................... 89 Physical Characteristics: Heat ............................................................................ 89 Physical Characteristics: Cold ............................................................................ 90 Frequency of Occurrence ................................................................................... 91 Vulnerability ........................................................................................................ 92 Hazard Mitigation Strategies............................................................................... 92 Storms: Hail ................................................................................................................... 94 Physical Characteristics ..................................................................................... 94 Frequency of Occurrence ................................................................................... 95 Vulnerability ........................................................................................................ 97 Hazard Mitigation Strategies............................................................................... 98 Storms: Lightning .......................................................................................................... 99 Physical Characteristics ..................................................................................... 99 Frequency of Occurrence ................................................................................. 100 Vulnerability ...................................................................................................... 100 Hazard Mitigation Strategies............................................................................. 101 Storms: Thunderstorms ............................................................................................... 102 Physical Characteristics ................................................................................... 102 Frequency of Occurrence ................................................................................. 103 Vulnerability ...................................................................................................... 105 Hazard Mitigation Strategies............................................................................. 105 Storms: Tornadoes and High Winds............................................................................ 106 Physical Characteristics ................................................................................... 107 Frequency of Occurrence ................................................................................. 109 Vulnerability ...................................................................................................... 110 Hazard Mitigation