I SECTION 2: PLAN UPDATE CITY OF LA CAÑADA FLINTRIDGE LOCAL HAZARD MITIGATION PLAN One Civic Center Drive, La Cañada Flintridge, CA 91011 (This page is intentionally left blank) Contents 1 INTRODUCTION 1 1.1 Why Prepare this Plan ..................................................................................................... 2 1.2 Updating the Plan ............................................................................................................. 2 1.3 Who Will Benefit .............................................................................................................. 3 2 PLAN UPDATE 4 2.1 Planning Process ............................................................................................................... 5 2.2 How it was Prepared ........................................................................................................ 7 2.3 Public Involvement ........................................................................................................... 7 2.3.1 Outreach Strategy 7 2.3.2 Public Meetings 8 2.4 Plan Mission and Goal ..................................................................................................... 9 3 PLAN MAINTENANCE 11 3.1 Monitoring and Review.................................................................................................. 12 3.1.1 Plan Monitoring 12 3.1.2 Plan Evaluation 12 3.1.3 Plan Updates 13 3.1.4 Continued Public Involvement 14 3.2 Plan Adoption ................................................................................................................. 14 3.3 Implementation Through Existing Programs .............................................................. 14 3.3.1 Update of Mitigation Efforts 15 4 COMMUNITY PROFILE 16 4.1 Geography ....................................................................................................................... 17 4.2 Historical ......................................................................................................................... 17 4.2.1 Major Past Events 18 4.3 Physical Setting ............................................................................................................... 19 4.3.1 Topology 19 4.3.2 Geology 20 4.3.3 Climate 20 4.4 Development Profile ....................................................................................................... 21 4.4.1 Land Use 21 4.4.2 Housing and Community Development 23 iv 4.4.3 Critical Facilities and Infrastructure 23 4.5 Community Demographic Profiles ............................................................................... 25 4.5.1 Population Demographics 25 4.5.2 Age Distribution 25 4.5.3 Race 26 4.6 Economy .......................................................................................................................... 27 4.6.1 Income 27 4.6.2 Industry, Businesses, and Institutions 27 4.6.3 Employment Trends 28 4.7 Transportation ................................................................................................................ 28 4.8 Schools ............................................................................................................................. 29 5 RISK ASSESSMENT 30 5.1 Hazard Identification and Approach ............................................................................ 31 5.1.1 Identified Hazards of Concern 31 5.1.2 Inventory of Community Assessments 33 5.1.3 Risk Analysis 34 5.1.4 Vulnerability Assessment 34 5.2 Action Plan Implementation .......................................................................................... 34 5.2.1 Status of Mitigation Action Items 34 5.2.2 Mitigation Action Items 34 5.3 Federal Guidelines .......................................................................................................... 35 5.4 Data Sources ................................................................................................................... 35 5.5 Limitations ...................................................................................................................... 35 5.6 Benefit-Cost Analysis ..................................................................................................... 35 6 CAPABILITIES ASSESSMENT 44 6.1 Capabilities Assessment ................................................................................................. 45 6.1.1 Planning and Regulatory 45 6.1.2 Administrative and Technical 47 6.1.3 Fiscal Mitigation Capabilities 50 6.1.4 Education and Outreach 51 7 EARTHQUAKE 53 7.1 General Background ...................................................................................................... 54 7.1.1 Causes 54 7.1.2 Characteristics 55 7.2 Hazard Profile ................................................................................................................ 57 7.2.1 Past Events 57 v 7.2.2 Locations 58 7.2.3 Frequency 59 7.2.4 Severity 59 7.2.5 Warning Time 60 7.3 Secondary Impacts ......................................................................................................... 61 7.4 Risk Assessment .............................................................................................................. 61 7.4.1 Exposure Assessment 61 7.4.2 Vulnerability Assessment 64 7.5 Mitigation Strategy ........................................................................................................ 67 7.5.1 Goals and Objectives 67 7.5.2 Previous Plan Mitigation Action Items 68 7.5.3 Current Mitigation Action Items 69 7.5.4 Action Plan and Implementation 71 7.6 Resource Directory ......................................................................................................... 71 7.6.1 Local Resources 71 7.6.2 State Resources 72 7.6.3 Federal Resources 73 7.6.4 Publications 74 7.7 Sources ............................................................................................................................ 75 8 FLOOD 76 8.1 General Background ...................................................................................................... 77 8.1.1 Causes and Characteristics 77 8.2 Hazard Profile ................................................................................................................ 78 8.2.1 Past Events 78 8.2.2 Locations 80 8.2.3 Frequency 82 8.2.4 Severity 82 8.2.5 Warning Time 82 8.3 Secondary Impacts ......................................................................................................... 83 8.3.1 Debris Flow 83 8.4 Risk Assessment .............................................................................................................. 83 8.4.1 Exposure Assessment 83 8.4.2 Vulnerability Assessment 85 8.5 Mitigation Strategy ........................................................................................................ 88 8.5.1 Goals and Objectives 88 8.5.2 Previous Plan Mitigation Action Items 89 8.5.3 Current Mitigation Action Items 90 8.5.4 Action Plan and Implementation 91 8.6 Resource Directory ......................................................................................................... 91 8.6.1 Local Resources 91 vi 8.6.2 State Resources 92 8.6.3 Federal Resources 93 8.6.4 Publications 97 8.7 Sources ............................................................................................................................ 97 9 LANDSLIDE 98 9.1 General Background ...................................................................................................... 99 9.1.1 Causes and Characteristics 99 9.1.2 What is a Debris Flow? 99 9.1.3 Landslide and Events Impacts 100 9.1.4 Landslide Conditions 100 9.2 Hazard Profile .............................................................................................................. 101 9.2.1 Past Events 101 9.2.2 Locations 103 9.2.3 Frequency 105 9.2.4 Severity 105 9.2.5 Warning Time 105 9.3 Secondary Impacts ....................................................................................................... 106 9.4 Risk Assessment ............................................................................................................ 106 9.4.1 Exposure Assessment 106 9.4.2 Vulnerability Assessment 108 9.5 Mitigation Strategy ...................................................................................................... 110 9.5.1 Landslide Building / Zoning Codes 110 9.5.2 Goals and Objectives 110 9.5.3 Previous Plan Mitigation Action Items 111 9.5.4 Current Mitigation Action Items 111 9.5.5 Action Plan and Implementation 113 9.6 Resource Directory ....................................................................................................... 113 9.6.1 Local Resources 113 9.6.2 State Resources 113 9.6.3 Federal Resources 115 9.6.4 Publications 115 9.7 Sources .......................................................................................................................... 116 10 WILDFIRE 117 10.1 General Background .................................................................................................... 118 10.1.1 Causes and Characteristics 118 10.2 Hazard Profile .............................................................................................................. 119 10.2.1 Past Events 119 10.2.2 Locations 119 10.2.3 Frequency 119 10.2.4 Severity 120 vii 10.2.5 Warning Time 120 10.3 Secondary Impacts ....................................................................................................... 120 10.4 Risk Assessment ............................................................................................................ 120