City of Unalaska Hazard Mitigation Plan December 4, 2013 Photo by J. Dickson This document was prepared under a grant from the Federal Emergency Management Agency (FEMA)'s Grant Programs Directorate, U.S. Department of Homeland Security, and the Alaska Division of Homeland Security and Emergency Management. Points of view or opinions expressed in this document are those of the authors and do not necessarily represent the official position or policies of FEMA's Grant Programs Directorate, the U.S. Department of Homeland Security, or the State of Alaska. This page intentionally left blank. City of Unalaska Hazard Mitigation Plan Executive Summary The City of Unalaska is following the lead of state and federal authorities in adopting an “All Hazards” approach to its emergency planning activities. The Unalaska All-Hazard Mitigation Plan (HMP) is a joint planning effort by the City of Unalaska, Qawalangin Tribe of Unalaska, and Ounalashka Corporation. This HMP is intended to serve Unalaska Island citizens and decision makers to implement actions that would reduce or eliminate future and potentially damaging natural hazard event impacts to their critical facilities and population. This HMP was drafted and adopted to fulfill requirements mandated by the Disaster Mitigation Act of 2000, under Public Law 106-390, amending the Robert T. Stafford Disaster Relief and Emergency Assistance Act, and Title 42 of the United States Code (5121 et seq). Local and Tribal governments are required to have a FEMA approved, City government adopted, and Tribal commitment for implementation (as appropriate) of natural hazard mitigation plan initiatives. The methodology used for developing the Unalaska Hazard Mitigation Plan consisted of the following tasks: Plan development, review, and maintenance Public and agency coordination and involvement Critical facility inventory development Hazard impact area identification and description Population risk assessment and critical facility vulnerability identification Mitigation strategy development identifying, selecting, prioritizing, and implementing mitigation actions Local HMP adoption following a public hearing Tribal HMP implementation commitment Periodic evaluation, review, and update The HMP is divided into eight sections: introduction, community description, planning process, HMP adoption, hazard profiles, vulnerability analysis, Mitigation strategy, and reference list, and appendices. Unalaska is at risk from seven natural hazards: earthquakes, erosion, flood, ground failure, severe weather, tsunamis, and volcanic activity. The primary threat to Unalaska is from severe weather and storm events. The other natural hazard threats to Unalaska are volcanic activity, earthquakes, and tsunamis. Planning Team identified mitigation measures include: Promote recognition and mitigation of all natural hazards that affect the City of Unalaska (City), Qawalangin Tribe of Unalaska, and Ounalashka Corporation. Reduce possibility of losses from all natural hazards that affect the City. Cross reference Mitigation goals and actions with other City planning mechanisms and projects. Reduce vulnerability of structures to earthquake, erosion, flood, ground failure, tsunami, volcano, and severe weather damages. Maintaining city monitoring and warning systems, i.e. the City of Unalaska’s Department of Public Safety warning siren system. The plan will be monitored, reviewed, and evaluated annually; and updated every five years. It will also be reviewed and updated as appropriate, such as when new funding sources become available, or after a disaster occurs that significantly affects Unalaska. In the event of a disaster, the update will be completed as soon as possible, but no later than the 12 months following the date the disaster occurs. This plan serves as guidance for citizens and policy makers in Unalaska in order to mitigate potential natural hazard disaster damages. The purpose of the HMP is to ensure public awareness and involvement, and maintenance of hazard mitigation initiatives to best protect Unalaska and mitigate damages from natural hazards. Periodic review of this plan is necessary in order to continually evaluate its effectiveness and to make the most efficient use of mitigation resources as they become available. The Unalaska Hazard Mitigation Plan developed initiatives will be incorporated into co-related to existing City, Tribal, and Corporation planning initiatives such as the Comprehensive, Capital Improvement, and the City Emergency Operations Plans. City of Unalaska Hazard Mitigation Plan Table of Contents 1. Introduction .......................................................................................................... 1-1 1.1 Hazard Mitigation Planning ..................................................................... 1-1 1.2 Grant Programs with Mitigation Plan Requirements ............................... 1-1 1.2.1 Hazard Mitigation Assistance (HMA) Unified Programs ........... 1-2 2. Community Description ....................................................................................... 2-1 2.1 Location, Geography, and History ........................................................... 2-1 2.2 Demographics .......................................................................................... 2-3 2.3 Economy .................................................................................................. 2-4 3. Planning Process .................................................................................................. 3-9 3.1 Planning Process Overview ..................................................................... 3-9 3.2 Hazard Mitigation Planning Team ......................................................... 3-10 3.3 Public Involvement & Opportunity for Interested Parties to participate ............................................................................................... 3-11 3.4 Incorporation of Existing Plans and Other Relevant Information ......... 3-13 3.5 Plan Maintenance ................................................................................... 3-14 3.5.1 Implementation Into Existing Planning Mechanisms ................ 3-14 3.5.2 Continued Public Involvement .................................................. 3-15 3.5.3 Monitoring, Reviewing, Evaluating, and Updating the HMP ........................................................................................... 3-15 4. Plan Adoption ...................................................................................................... 4-1 4.1 Adoption by Local Governing Bodies and Supporting Documentation ......................................................................................... 4-1 5. Hazard Profiles..................................................................................................... 5-1 5.1 Overview of a Hazard Analysis ............................................................... 5-1 5.2 Hazard Identification and Screening ........................................................ 5-1 5.3 Hazard Profile .......................................................................................... 5-3 5.4 Natural Hazards ....................................................................................... 5-5 5.4.1 Earthquake ................................................................................... 5-5 5.4.2 Erosion ....................................................................................... 5-14 5.4.3 Flood .......................................................................................... 5-25 5.4.4 Ground Failure ........................................................................... 5-30 5.4.5 Tsunami and Seiche ................................................................... 5-35 5.4.6 Volcanic Hazards ....................................................................... 5-39 5.4.7 Weather (Severe) ....................................................................... 5-52 5.5 Technological and Manmade Hazards ................................................... 5-59 5.5.1 Transportation System Disruptions ............................................ 5-59 6. Vulnerability Analysis ......................................................................................... 6-1 6.1 Vulnerability Analysis Overview ............................................................ 6-1 6.2 Land Use and Development Trends ......................................................... 6-2 6.2.1 Land Use ...................................................................................... 6-2 6.3 Vulnerability Exposure Analysis For Current Assets .............................. 6-8 6.3.1 Asset Inventory ............................................................................ 6-8 6.4 Repetitive Loss Properties ..................................................................... 6-20 6.4.1 NFIP Participation ..................................................................... 6-20 6.5 Vulnerability Analysis Methodology ..................................................... 6-20 i City of Unalaska Hazard Mitigation Plan 6.6 Data Limitations ..................................................................................... 6-21 6.7 Vulnerability Exposure Analysis ........................................................... 6-22 6.7.1 Exposure Analysis – Hazard Narrative Summaries ................... 6-24 6.8 Future Development ............................................................................... 6-28 (DCRA