Mono County Multi-Jurisdictional Local Hazard Mitigation Plan (LHMP) Mono County Town of Mammoth Lakes OCTOBER 2006 Mono County Multi-Jurisdictional Local Hazard Mitigation Plan (LHMP) Mono County Town of Mammoth Lakes Prepared By: Mono County Community Development Department P.O. Box 347 Mammoth Lakes, CA 93546 (760) 924-1800, fax (760) 924-1801 [email protected] Mono County Local Hazard Mitigation Plan The Mono County Local Hazard Mitigation Plan is intended to be a living document that changes over time as circumstances change and new information becomes available. To suggest amendments to the plan, or to request further information concerning the plan, contact the Mono County Community Development Department. You may also visit the Mono County website or the Town of Mammoth Lakes website (www.monocounty.ca.gov or www.ci.mammoth-lakes.ca.us) to view the document online. The Mono County and Town of Mammoth Lakes websites also include a complete listing of staff members and their contact information. Mono County Community Development Department [email protected] (760) 924-1800 (Mammoth Lakes) (760) 932-5430 (Bridgeport) Mono County CDD Box 8 Bridgeport, CA 93517 Mono County CDD Box 347 Mammoth Lakes, CA 93546 Town of Mammoth Lakes Community Development Department www.ci.mammoth-lakes.ca.us (760) 934-8989 Town of Mammoth Lakes Community Development Department P.O. Box 1609 Mammoth Lakes, CA 93546 TABLE OF CONTENTS Resolutions of Adoption ............................................................................................. iii Guide to Using the LHMP ............................................................................................ xi I. Planning Process ....................................................................................................... 1 Focus of the Plan .................................................................................................. 1 Relationship Between the LHMP & Local Emergency Operation Plans ..... 1 Planning Process & Participants ........................................................................ 2 Public Involvement .............................................................................................. 3 Incorporation of Prior Studies ............................................................................ 4 II. Local Capabilities Assessment ............................................................................. 6 Available Resources for Hazards Mitigation Planning .................................. 6 Human Resources .................................................................................................6 Technical Resources ..............................................................................................8 Local Mitigation Funding Sources ..................................................................... 9 Local Hazard Ordinances ................................................................................. 10 Ongoing Hazards Mitigation ........................................................................... 11 III. Risk Assessment................................................................................................. 18 Natural Hazards Affecting Mono County ..................................................... 18 Mono County Disaster Declarations Since 1950 ............................................ 19 Risk Assessment—Specific Hazards ............................................................... 21 Avalanche Hazards .......................................................................................23 Dam Failure Hazards ...................................................................................29 Flood Hazards ...............................................................................................34 Landslide Hazards ........................................................................................43 Seismic Hazards ............................................................................................48 Severe Winter Storm Hazards .....................................................................57 Volcanic Hazards ..........................................................................................62 Wildfire Hazards ...........................................................................................68 Vulnerability to Identified Hazards: Overview ............................................ 78 Vulnerability: Structures .................................................................................. 79 Estimating Losses ............................................................................................... 80 Development Trends ......................................................................................... 80 Local Hazard Concerns ..................................................................................... 82 i Mono County LHMP October 2006 IV. Mitigation Strategy ............................................................................................. 84 Mitigation Overview ......................................................................................... 84 Proposed Mitigation Actions and Projects ..................................................... 86 V. Plan Maintenance............................................................................................... 101 Monitoring, Evaluating, & Updating the Plan ............................................ 101 Incorporating the LHMP Into Other Planning Documents ....................... 102 Continued Public Involvement ...................................................................... 102 VI. References ........................................................................................................... 104 VII. Appendix A—Map Set .................................................................................... A-1 VII. Appendix B—Existing Hazard Policies ....................................................... B-1 TABLES Table 1 Mono County Disaster Declarations Since 1950 ............................................. 19 Table 2 Natural Hazards in Mono County .................................................................... 20 Table 3 Dams and Reservoirs in Mono County ............................................................ 30 Table 4 Mono County, Average Annual Flow, Selected Streams .............................. 34 Table 5 Communities at Risk From Wildland Fires, Mono County .......................... 68 ii Mono County LHMP October 2006 Resolutions of Adoption Resolutions of Adoption from Town of Mammoth Lakes Town Council and Mono County Board of Supervisors: iii Mono County LHMP October 2006 iv Mono County LHMP October 2006 v Mono County LHMP October 2006 vii Mono County LHMP October 2006 viii Mono County LHMP October 2006 ix Mono County LHMP October 2006 x Mono County LHMP October 2006 Guide to Using the LHMP Purpose of the Local Hazard Mitigation Plan The Local Hazard Mitigation Plan (LHMP) is a planning document for hazards mitigation, focusing primarily on natural hazards as required by State and Federal law. Its purpose is to identify natural hazards in the area and ways to mitigate the impacts of those hazards before they occur. The intent of the LHMP is to minimize impacts to people and property from identified natural hazards. It is not intended to provide response scenarios for emergency events. Emergency Operations Plans Both the Town of Mammoth Lakes and Mono County have Emergency Operations Plans (EOPs) that address specific emergency procedures for a variety of events, including natural hazard events, terrorism, airplane crashes, bioterrorism, etc. The EOPs are specific response plans for emergency response situations. These plans are maintained by the County Office of Emergency Services and by the Town’s Police Department and include lists of emergency response personnel as well as procedures for responding to a variety of events. The plans are updated annually. LHMP Contents The LHMP establishes a planning process for developing the document, incorporates applicable prior hazard studies, assesses the resources available for hazards mitigation planning, including existing ongoing hazards planning and mitigation for the area, identifies natural hazards affecting the area and assesses the risk to people and property from those hazards, and provides mitigation strategies for minimizing the impacts of identified hazards. A separate map set in Appendix A contains various maps and figures pertaining to hazards that affect communities in Mono County. xi Mono County LHMP October 2006 I. PLANNING PROCESS FOCUS OF THE PLAN The Mono County Local Hazard Mitigation Plan (LHMP) is a multi-jurisdictional hazard plan that addresses the unincorporated areas of Mono County as well as the Town of Mammoth Lakes, the county's only incorporated area. It also considers areas outside the county that either may impact areas within the county or that are accessed from the county; e.g., Rock Creek Lake in Inyo County could affect Mono County and Red’s Meadow in Madera County is accessed from Mono County. Mono County is a sparsely populated rural county located on the eastern side of the Sierra Nevada mountain range. The State of Nevada forms the county's eastern border. Approximately 94 percent of the County's 3,103 square miles are publicly owned; the area's spectacular scenery of high valleys and rugged mountain ranges has made it a popular recreation destination. The major population center, and the County's only incorporated