CITY OF MANCHESTER, NEW HAMPSHIRE HAZARD MITIGATION PLAN 2018 i ii CITY OF MANCHESTER NEW HAMPSHIRE HAZARD MITIGATION PLAN October 2018 Prepared by the Southern New Hampshire Planning Commission The preparation of this document has been financed in part by a grant from the State of New Hampshire Department of Safety, Homeland Security and Emergency Management iii Acknowledgements We would like to thank the following people for contributing their time and effort to complete the Manchester Hazard Mitigation Plan: Manchester Hazard Mitigation Committee Members Kevin M. Healey - Captain, Emergency Mgmt. Coordinator-Manchester Fire Dept. and Elliot Health Systems Brett French - Manchester Fire Department, Lieutenant Phil Alexakos - Manchester Health Department Jennie Angell - Director, Information Systems Jeff Belanger - Planning and Community Development Paul Blais - Emergency Manager Catholic Medical Center Michael Carr - Manchester Health Department Will Craig - Eversource, Community Relations Specialist Heather Dunkerley - NH Homeland Security and Emergency Management Field Rep. Bob Field - Manchester Fire Department, Training Josh Gagne - Department of Public Works-Facilities Hannah Koehler - Manchester Fire Department Intern Mike Landry - Planning and Community Development Peter Lennon - Manchester Fire Department, Fire Marshall Eric Levesque - Information Systems Sarah Morris - Manchester Health Department Chris Proulx - Department of Public Works TJ Rapson - Manchester Fire Department Intern Melanie Sanuth - Economic Development Director, Manchester Thanks also to: • The New Hampshire Department of Safety, Homeland Security and Emergency Management, which developed the New Hampshire Natural Hazards Mitigation Plan; • The Southwest Region Planning Commission, which developed Hazard Mitigation Planning for New Hampshire Communities; and • The Bedford, Chester, Derry, Goffstown, Hooksett, New Boston, and Weare Hazard Mitigation Committees and their respective Hazard Mitigation Plans. • Jacqueline Cardoza and Justin Kates of Nashua OEM. • Sylvia von Aulock, Derek Shooster, Cameron Prolman, and Maddie DiIonno of Southern NH Planning Commission. All the above publications served as models for this plan. iv Preface Hazard mitigation planning is a relatively new field of planning, spearheaded by the Federal Emergency Management Agency (FEMA) during the 1990’s after Hurricane Andrew caused more than $20 billion in damage across several southern states. That event resulted in 54 fatalities and the disruption of millions of lives. The Disaster Mitigation Act of 2000, developed by FEMA, was intended to help both communities and states prepare for, and deal with, such disasters. While New England normally does not have hurricanes of Andrew’s magnitude, this area does experience many types of natural disasters that cost both lives and money. Natural disasters can occur during all four seasons in the Northeast: winter ice, snow, and nor’easters; spring flooding; summer downbursts and thunderstorms; and fall hurricanes. Planning to make a community disaster-resistant before these storms occur can help save lives as well as homes and infrastructure. Several FEMA programs are designed to strengthen the nation’s disaster resistance by reducing risks. This means changing conditions and behaviors prior to disasters to protect lives and prevent the loss of property. Such measures include building safely within the floodplain or removing homes altogether, engineering buildings and infrastructure to withstand earthquakes, and creating and enforcing effective building codes to protect property from floods, hurricanes and other natural hazards. A community’s eligibility for hazard mitigation funding will depend upon it having adopted a hazard mitigation plan. Mitigation measures contained within the Manchester Hazard Mitigation Plan may be sufficient to warrant a grant to help pay for the proposed measures. It is hoped that this document will be a good first step toward analyzing natural hazards in Manchester, forecasting where potential disasters might occur, and reducing the impact on lives and the community. v Table of Contents Acknowledgements ............................................................................................ iv Preface .................................................................................................................... v Executive Summary ............................................................................................ ix I. INTRODUCTION The Hazard Mitigation Planning Process ..........................................................1 Jurisdiction .............................................................................................................2 Authority ................................................................................................................2 Scope of the Plan & Federal and State Participation ........................................2 What is Hazard Mitigation? ................................................................................3 Why Develop a Hazard Mitigation Plan? .........................................................3 Benefits of Hazard Mitigation .............................................................................3 Hazard Mitigation Planning Process & Methodology ....................................4 Tasks to Complete the Plan Update ...................................................................5 2018 Plan Update Public Committee Meetings ................................................6 Coordination with Other Agencies and Individuals .......................................6 Existing Manchester Emergency Operations Plan ...........................................7 Public and Stakeholder Involvement .................................................................7 Hazard Mitigation Goals and Objectives of the City of Manchester ...........10 II. COMMUNITY PROFILE Location, Population, Topography, and Climate ...........................................11 Current Land Use Development Trends in Manchester ...............................12 National Flood Insurance Program ..................................................................15 III. HAZARD IDENTIFICATION Disaster Risks, Extent, and Impacts .................................................................16 Flooding ....................................................................................................16 Hurricanes ................................................................................................17 Debris-Impacted Infrastructure and River Ice Jams ..........................19 Erosion, Mudslides, and Rapid Snowpack Melt ................................20 Dam Breach or Failure ............................................................................20 Water Retention Facility Failure ...........................................................22 Tornados ...................................................................................................24 Nor’easters ...............................................................................................25 Downbursts ..............................................................................................26 Lightning ..................................................................................................27 Fires ...........................................................................................................28 Heavy Snowstorms .................................................................................30 Ice Storms .................................................................................................33 HailStorms ...............................................................................................33 vi Earthquakes .............................................................................................35 Landslides ................................................................................................38 Geomagnetism .........................................................................................38 Utility Pipe Failure ..................................................................................38 Drought ....................................................................................................39 Extreme Heat ...........................................................................................40 Extreme Cold ...........................................................................................41 Avalanche .................................................................................................42 Large Trees Down Blocking Roads ......................................................43 Civil Disorder ..........................................................................................43 Terrorism ..................................................................................................43 Radon ........................................................................................................43 IV. ASSESSING PROBABILITY, SEVERITY, AND RISK Past and Potential Hazards ...............................................................................44 Hazard Vulnerability Assessment ....................................................................45 V. VULNERABILITY ASSESSMENT: IDENTIFICATION AND ESTIMATION OF LOSSES Disaster Risk and Vulnerability Assessment ..................................................46 Flooding ....................................................................................................47