Hazard Mitigation Plan 2010
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TOWN OF LONDONDERRY, NEW HAMPSHIRE Town of Londonderry, New Hampshire, Town Offices HAZARD MITIGATION PLAN 2010 ii TOWN OF LONDONDERRY NEW HAMPSHIRE HAZARD MITIGATION PLAN NOVEMBER 30, 2010 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. Acknowledgements Appreciation is extended to the following people for contributing their time and effort to complete the Londonderry Hazard Mitigation Plan: 2010 Londonderry Hazard Mitigation Committee Members Kevin MacCaffrie - Emergency Management Director, Fire Chief, Chair Richard G. Canuel - Senior Building Inspector/ Zoning Officer, Community Development Department Sharon Carson - Resident of the Town of Londonderry Tim Jones - Lieutenant, Londonderry Police Department Tim Thompson - Town Planner, Londonderry Community Development Department John R. Trottier - Assistant Director of Public Works and Engineering, Department of Public Works Jodie Levandowski - Intern, Londonderry Community Development Department John R. Gilcreast - Assistant Building Inspector, Community Development Department Thanks also to: • The New Hampshire Department of Safety, Division of Fire Safety and Emergency Management, Homeland Security and Emergency Management (NHHSEM), 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, Derry, Goffstown, Hooksett, Manchester and New Boston Hazard Mitigation Committees and their respective Hazard Mitigation Plans. All the above publications served as models for this plan. "We will of course be there to help after disaster strikes, but as you all know, there’s no substitute for mitigation before it does.... As a poet once wrote, "the test of men lies in action." We as emergency managers and first responders cannot afford to wait for action…. Through planning, mitigation, education, and cooperation, we can make sure our at-risk communities are prepared before the first drop of rain or gust of wind ever threatens our shores." —Joe Allbaugh, Director of FEMA, addressing the 2002 National Hurricane Conference i Preface Hazard mitigation planning is a relatively new field, spearheaded by the Federal Emergency Management Agency (FEMA) during the 1990s 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. These disasters and other natural hazards 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 events occur can help save lives as well as homes and infrastructure. FEMA has several programs designed to strengthen the nation’s disaster resistance by reducing risks, and changing conditions and behaviors before a disaster in order to protect lives and prevent the loss of property. FEMA has also raised its budget to upgrade the existing Flood Insurance Rate Maps through the Map Modernization project. Many communities have outdated maps that do not reflect the true extent of flooding potential. A community’s eligibility for hazard mitigation funding depends upon its having adopted a hazard mitigation plan that addresses these issues. Mitigation measures contained within the Londonderry Hazard Mitigation Plan may be sufficient to receive grant funding. It is hoped that this document will be a good first step toward analyzing hazards in Londonderry, forecasting where potential disasters might occur, and reducing their impact on people and the community. ii Table of Contents Acknowledgements .............................................................................................. i Preface.................................................................................................................... ii Executive Summary...........................................................................................vii I. INTRODUCTION Natural Hazards and Their Consequences .......................................................1 What Is Hazard Mitigation? ................................................................................2 Why Develop a Hazard Mitigation Plan? .........................................................2 Benefits of Hazard Mitigation.............................................................................3 Background: Londonderry Hazard Mitigation Planning ...............................3 Purpose.......................................................................................................3 Authority....................................................................................................3 Scope of the Plan .......................................................................................4 Methodology..............................................................................................4 2010 Plan Update Methodology .............................................................5 2010 Plan Update Public Committee Meetings ....................................5 Coordination with Other Agencies and Individuals ...........................5 Existing Londonderry Emergency Management Plan ....................................6 State of New Hampshire Legislation Related to Master Plans ......................6 Plan Development Steps 1-10..............................................................................7 Hazard Mitigation Goals for the Town of Londonderry ..............................10 II. HAZARD IDENTIFICATION Location, Population, Topography, and Climate...........................................12 Current Land Use Development Trends in Londonderry ............................13 National Flood Insurance Program..................................................................16 Past and Potential Hazards ...............................................................................17 A. Flooding..........................................................................................................17 1. Riverine flooding ....................................................................................17 2. Hurricanes................................................................................................18 3. Debris-impacted infrastructure and river ice jams ............................19 4. Erosion and mudslides...........................................................................20 5. Rapid snow pack melt............................................................................20 6. Dam breach or failure.............................................................................20 7. Other water retention facility failure ...................................................21 B. Wind................................................................................................................22 1. Hurricanes................................................................................................22 2. Tornados...................................................................................................22 3. Nor’easters ...............................................................................................23 4. Downbursts..............................................................................................24 5. Lightning..................................................................................................24 iii Table of Contents (continued) C. Fire...................................................................................................................25 1. Wild Land Fires.......................................................................................25 2. Target Hazards........................................................................................26 3. Isolated homes.........................................................................................26 D. Ice and Snow Events.....................................................................................27 1. Heavy snowstorms .................................................................................27 2. Ice storms .................................................................................................29 3. Hailstorms................................................................................................30 E. Seismic Events ...............................................................................................32 1. Earthquakes .............................................................................................31 2. Landslides ................................................................................................31 F. Other Hazards...............................................................................................33 1. Utility pipe failure...................................................................................33 2. Airport related disasters ........................................................................34