This document provides guidance on conducting hazard identification and risk assessment for a multi-jurisdictional hazard mitigation plan update. It outlines steps to identify natural hazards, describe their locations and impacts, analyze vulnerability to structures and development trends, and assess risk for each participating jurisdiction. The update should incorporate any new hazards or information that has changed vulnerability since the previous plan. Key elements include identifying and profiling hazards, assessing vulnerability of structures, analyzing development trends, addressing repetitive loss properties, and ensuring full coverage of risks for all participating communities.

1. Hazard Identification - Risk Assessment

2. Hazard Identification - Risk Assessment
Update information for all natural hazards
in the plan and add new hazards that can
cause damage:
• Flooding (riverine and flash floods)
(NOTE: Use D-FIRMS if available)
• Severe winter storms (blizzards, ice
storms, extreme cold)
• Severe summer storms (tornadoes,
hail, high winds, lightning)
• Landslides and subsidence
• Other hazards such as earthquakes,
levee/dam failures, extreme heat,
drought, wildfires, etc.

3. Risk Assessment – Identifying Hazards
The Plan Update:
• Identify and describe hazards likely to
affect the planning area
The Plan Will:
• Describe the sources used to identify
hazards
• Refer to the State risk assessment and
approach hazard identification similarly
• Include maps of hazard areas

4. Risk Assessment – Identifying Hazards
The Plan Update:
• Addresses any newly identified
hazards
The Update:
• Incorporates improved hazard
descriptions if available

5. Hazard Identification / Profiling
Risk Assessment: Hazard Identification and Selection
Hazard Hazard State or Hazard Hazard Occurrence
Type Identified in Presidential Identified in Rank s since
(Example) State HMP? Declaration? County? original
plan
approved?
Flood
Tornado
T-storm /
wind
Severe
Winter
Storm
Drought
Extreme
Temps

6. Risk Assessment - Profiling Hazards
The Plan Shall:
• Provide a description of previous
occurrences, location, extent (severity or
magnitude), and probability of future
occurrence for each identified hazard
Plan Update Shall:
• Continue to describe occurrences of hazards
included in the previous plan
• Incorporate any new historical records or
hazard data
• Address any data deficiencies that were
identified in the previous plan

7. Hazard Profiles
• Describe the recognized natural hazards
likely to affect the jurisdiction –
• Include updated info:
Nature: Description of the hazard
History: Past occurrences and details
Location: Area that is impacted
Extent: Range of potential
magnitude or severity
(example: EF1)
Probability: Statistical measures that the
event might happen

8. Hazard Profiles
The natural hazards are required to be
ranked. Example:
1. Flooding
2. Wildfire
3. Dam/Levee Failure
4. Drought

9. )
Example: Location, Extent (Red River 4/3/09 Image: USGS)

11. Assessing Vulnerability: Identifying Structures
• An overview of the community’s
vulnerability is a summary of the hazard’s
impact on the community and its
vulnerable structures.
• This summary shall include, by type of
hazard, a general description of the types
of structures affected by the hazards.
Examples include, but are not limited to,
buildings, infrastructure, critical facilities,
structures that house the elderly or
disabled, and areas where low-income
populations reside.

12. Assessing Vulnerability:
Identifying Structures
• The overview shall also include a general
description of the hazard’s impact to the
vulnerable structures. Vulnerable
structures include those located within
geographic areas susceptible to a
particular hazard. Certain hazards may
affect the entire community or planning
area.
o The summary can be presented in terms of
dollar value or percentages of damage.

13. Type of Number of Structures Value of Structures Number of People
Structure
# in Com- # in % in $ in Com- $ in % in # in # in % in
munity Hazard Hazard munity Hazard Hazard Com- Hazard Hazard
Area Area Area Area munity Area Area
Residential 61 16 25 3.92m .44m 11 403 69 7
Commercial 5 4 80 6.50m 4.5m 69 570 345 61
Industrial 0 0 0 0 0 0 0 0 0
Agricultural 2 1 50 .175m 0.9m 51 10 5 50
Government 7 5 71 7.05m 2.5m 36 570 170 30
Education 1 1 100 .50m 0.50m 100 125 125 100
Utilities 2 2 100 2.75m 2.75m 100 15 15 100
Total 81 30 37 24.3m 11.8m 49 2,044 730 44

14. Assessing Vulnerability: Overview
Notes about the previous chart:
1. The summary is for one hazard to one
community in the plan.
2. This is an estimate. The assumptions
going into the estimate should be
stated. Examples: source of data, how
value of structures were estimated
and how the percent in hazard area
was determined.
3. Please consult with mitigation staff if
using an alternate method.

15. Assessing Vulnerability: Overview
The Plan Shall:
• Provide a general description of the
types of structures affected by each
hazard
• Provide a general description of each
hazards impact to vulnerable
structures
Plan Update Shall:
• Describe any changes, clarifications, or
refinements to the overview summary
• Address how previously identified data
limitations were addressed and
incorporated

16. Assessing Vulnerability: Overview
The Update Should:
• Should take into account updates to
inventories of existing structures in
hazard areas
• Describe changes in methodology

17. EXAMPLE: Risk Assessment –
Assessing Vulnerability
Estimating Potential Losses
17

18. *New* Assessing Vulnerability: Repetitive Loss
Properties
Local Mitigation Plans must address
repetitive loss structures in the risk
assessment by:
1. describing the types of structures
2. estimated numbers
3. general location of repetitive loss
properties located in identified
flood hazard areas

19. *New* Assessing Vulnerability: Repetitive
Loss Properties
The plan should also:
•Describe vulnerability in terms of
estimated potential dollar loss
•Describe vulnerability in terms of land
use and development trends
•Include a map of known flood hazards

20. Example 1
Repetitive Loss Repetitive Loss Repetitive Loss
Jurisdiction NFIP CID Floodplain
Residential Commercial Industrial
Franklin 390167 Darby Creek # of homes # of structures # of structures
County $ lost $ lost $ lost
Scioto River # of homes # of structures # of structures
$ lost $ lost $ lost
Olentangy River # of homes # of structures # of structures
$ lost $ lost $ lost
Alum Creek # of homes # of structures # of structures
Columbus
$ lost $ lost $ lost
Big Walnut # of homes # of structures # of structures
$ lost $ lost $ lost
Creek
Blacklick Creek # of homes # of structures # of structures
$ lost $ lost $ lost
See map on Walnut Creek # of homes # of structures # of structures
page xx $ lost $ lost $ lost

21. Example 2
“Jurisdiction A” has been a member of the NFIP
since 1979. Their current floodplain ordinance
was adopted in 1998. Two floods occurred on
Walnut Creek (1985 and 2004). Four insured
homes, built before 1979, were flooded in 1985. In
2004, another smaller flood occurred. Two homes
were again flooded. These two homes suffered
about $7,000 in damage. They are repetitive loss
structures. “Jurisdiction A” has added mitigation
actions to elevate these two homes.
(NOTE: Privacy laws prevent use of addresses)

22. Risk Assessment
Assessing Vulnerability: Analyzing Development Trends
The Plan Should:
• Provide a general overview of land uses and
development trends within the planning area
• Describe trends in terms of amount of change
over time and identify where it is occurring
• Differentiate land uses of similar types that
have distinctly different densities
• Analyze where future land use changes and
growth are likely to occur

23. Risk Assessment
Assessing Vulnerability: Analyzing Development Trends
Plan Update Should:
• Highlight any development changes
since previous plan

24. Risk Assessment - Multi-Jurisdictional
The Plan Shall:
• Present risk assessment information
for the planning area as a whole
• Include information for localized
hazards

25. Risk Assessment - Multi-Jurisdictional
Plan Update Shall:
• Attribute any newly identified risks to the
appropriate jurisdiction or to the planning are
as a whole
• Incorporate any new information that
changes the vulnerability to the previously
identified hazards

26. Risk Assessment
• Make sure all participating communities
are covered.
• If risk and vulnerability are the same for
each city…indicate this!!!
• Show differences in communities where
appropriate
• Most important for Site-specific hazards

27. Questions? Comments?