RESOLUTION NUMBER 7660 A RESOLUTION OF THE MISSOULA CITY COUNCIL TO ADOPT A PRE-DISASTER MITIGATION PLAN UPDATE WHICH WILL GUIDE THE CITY IN MAKING DECISIONS FOR PRE-DISASTER MITIGATION PROJECTS AND ALLOW THE CITY TO BE ELIGIBLE TO RECEIVE FEDERAL PRE- AND POST-DISASTER MITIGATION FUNDS. WHEREAS, all citizens and property within the City of Missoula are at risk from a wide range of hazards, such as, but not limited to, flooding, earthquakes, winter storms, wind and thunderstorms, wildfire, landslides, and volcanic hazards, and; WHEREAS, the Missoula City Council recognizes that mitigation is the most cost effective way to manage the potential consequences of disasters, and; WHEREAS, a Pre-Disaster Mitigation Plan will guide the City in making decisions for pre-disaster mitigation projects, and; WHEREAS, the Federal Emergency Management Agency requires local jurisdictions to have an approved Pre-Disaster Mitigation Plan to be eligible for federal pre- or post-disaster mitigation monies, and; WHEREAS, the 2004 Pre-Disaster Mitigation Plan was prepared in accordance with guidance provided by FEMA under the Disaster Mitigation Act of 2000, and; WHEREAS, the 2004 Pre-Disaster Mitigation Plan provides the background and essentials for evaluating risks and exposures to hazards, and; WHEREAS, this 2011 Pre-Disaster Mitigation Plan Update has been prepared according to "Local Multi- Hazard Mitigation Planning Guidance" (FEMA, 2008) and adds to the 2004 Pre-Disaster Mitigation Plan. NOW, THEREFORE, BE IT RESOLVED, that the City of Missoula, Montana hereby adopts, the Pre- Disaster Mitigation Plan Update dated August, 2011. PASSED AND ADOPTED this 24th day of October, 2011 ATTEST: APPROVED: /s/ Martha L. Rehbein /s/ John Engen Martha L. Rehbein, CMC John Engen City Clerk Mayor (SEAL). PRE-DISASTER MITIGATION PLAN 2011 UPDATE MISSOULA COUNTY CITY OF MISSOULA August 2011 Prepared for: Missoula County and City of Missoula 201 West Broadway 435 Ryman Missoula, Montana 59802 Missoula, Montana 59802 Prepared by: Atkins 1120 Cedar Street Missoula, Montana 59802 Missoula County/City of Missoula PDM Plan Update Resolution for Plan Update Adoption Missoula County i Missoula County/City of Missoula PDM Plan Update Resolution for Plan Update Adoption City of Missoula ii Missoula County/City of Missoula PDM Plan Update TABLE OF CONTENTS Resolution for Plan Adoption Missoula County ........................................................................................................................................... i City of Missoula ........................................................................................................................................... ii 1.0 INTRODUCTION ........................................................................................................................... 1-1 1.1 Project Area Location .............................................................................................................. 1-1 1.2 Local Economy ........................................................................................................................ 1-2 1.3 Land Use Trends ...................................................................................................................... 1-2 1.4 Scope and Plan Organization ................................................................................................... 1-4 2.0 PLANNING PROCESS AND PUBLIC INVOLVEMENT ......................................................... 2-1 2.1 Local Emergency Planning Committee (LECP) ...................................................................... 2-1 2.2 Public Meetings ........................................................................................................................ 2-1 3.0 INVENTORY OF COMMUNITY ASSETS ................................................................................ 3-1 3.1 Critical Facilities ...................................................................................................................... 3-1 3.1.1 Essential Facilities ....................................................................................................... 3-1 3.1.2 Lifeline Utility Systems ............................................................................................... 3-2 3.1.3 Transportation Systems .............................................................................................. 3-3 3.1.4 Hazardous Material Facilities ...................................................................................... 3-3 3.1.5 Other Essential Buildings & Facilities ........................................................................ 3-4 3.2 Building Structures and Improvements ................................................................................... 3-4 3.3 Population ................................................................................................................................ 3-5 3.3.1 Total Population .......................................................................................................... 3-5 4.0 MISSOULA COUNTY HAZARD RISK ASSESSMENT ........................................................... 4-1 4.1 Overview .................................................................................................................................. 4-1 4.1.1 Hazard Assessment Methodology ............................................................................... 4-1 4.2 Earthquakes .............................................................................................................................. 4-2 4.2.1 Background ................................................................................................................. 4-2 4.2.2 Magnitude/Frequency .................................................................................................. 4-4 4.2.3 Loss Estimation ........................................................................................................... 4-5 4.3 Flooding ................................................................................................................................... 4-6 4.3.1 Flooding – Regional and Flash .................................................................................... 4-6 4.3.1.1 Participation in the Flood Insurance Program ............................................. 4-7 4.3.1.2 Magnitude/Frequency .................................................................................. 4-7 4.3.1.3 Loss Estimate ............................................................................................ 4-11 4.3.2 Flooding – Ice Jams ................................................................................................... 4-13 4.3.2.1 Magnitude/Frequency ................................................................................ 4-13 4.3.2.2 Loss Estimate ............................................................................................ 4-15 4.3.3 Flooding - Dam Failure ............................................................................................. 4-15 4.3.3.1 Dams within Missoula County .................................................................. 4-15 4.3.3.2 Dams Upstream from Missoula County .................................................... 4-17 4.3.3.3 Inundation Maps ........................................................................................ 4-18 4.3.3.4 Loss Estimate ............................................................................................ 4-19 4.4 Landslide ................................................................................................................................ 4-20 4.4.1 Magnitude/Frequency ................................................................................................ 4-20 4.4.1.1 Landslides after Forest Fires ..................................................................... 4-20 4.4.1.2 Other Landslides in Missoula County ....................................................... 4-21 4.4.2 Loss Estimate ............................................................................................................ 4-21 iii Missoula County/City of Missoula PDM Plan Update 4.5 Volcano .................................................................................................................................. 4-22 4.5.1 Magnitude/Frequency ................................................................................................ 4-23 4.5.2 Loss Estimate ............................................................................................................ 4-25 4.6 Weather (Storms and Wind) .................................................................................................. 4-25 4.6.1 Severe Thunderstorms ............................................................................................... 4-25 4.6.1.1 Magnitude/Frequency ................................................................................ 4-25 4.6.1.2 Loss Estimate ............................................................................................ 4-26 4.6.2 Winter Storms and Cold Spells ................................................................................. 4-27 4.6.2.1 Magnitude/Frequency ................................................................................ 4-27 4.6.2.2 Loss Estimate ............................................................................................ 4-27 4.7 Wildfire .................................................................................................................................