Last updated: · Scores from FEMA’s National Risk Index (December 2025)
Montgomery County, Maryland's most populous, expects to lose $71.0 million a year to inland flooding, more than any other Maryland jurisdiction and 56% of its $126.4 million total. FEMA mitigation grants in the county add up to $4.0 million since fiscal 1989: 3% of the state's mitigation money for 12% of its expected losses.
What drives the risk
The losses are mostly damage to buildings, 77% of the total, and FEMA's model counts rain that overwhelms storm drains as well as streams that leave their banks. The county's own explanation fits: its Department of Environmental Protection says flooding events have increased, with more impervious surface from development and more high-intensity rain among the top reasons, and that urban flooding areas are typically not mapped.
Hurricanes, at $12.5 million a year, and heat waves, at $10.9 million, trail well behind. The county's social vulnerability is very low and its community resilience relatively high, which keeps its overall risk rating relatively moderate despite losses that rank third in the state.
Where the mitigation money has gone
FEMA lists 13 funded projects, including $700 thousand in Flood Mitigation Assistance for Rockville's Flood Resiliency Master Plan in fiscal 2022. The largest, $1.4 million under the Hurricane Isabel declaration in fiscal 2003, paid for floodproofing and a flood berm. Five generator grants, most of them to Rockville, followed. The newest, $739 thousand obligated in fiscal 2024, is congressionally directed money for storm drain improvements in Rockville's Potomac Woods neighborhood, which flooded during Tropical Storm Ida in 2021.
Montgomery has no funded projects under DR-4491, Maryland's COVID-19 declaration, whose mitigation money reached 17 of the state's 24 jurisdictions.
The mitigation plan
The 2024 Montgomery County Hazard Mitigation Plan covers the county and 17 municipalities, and FEMA's approval runs through June 24, 2029. The county wrote it alongside its Climate Action Plan, pairing climate resilience strategies with hazard mitigation. Separately, the Department of Environmental Protection is building a county flood management plan around a new flood model: eleven watersheds covering just over 101,000 acres, home to nearly two-thirds of residents, with three finished and the rest scheduled through February 2029.
What we'd look at next
Montgomery is building flood data that goes beyond FEMA's maps, with a model that reaches the urban flooding those maps leave out. The test is what comes after each watershed study. We'd want every one to end in a short list of designed, costed projects that can compete for FEMA money the next time a disaster is declared, because a grant record of $4.0 million since 1989 shows how little federal mitigation money has followed the county's flood risk so far.
Hazards ranked by expected annual loss
What FEMA expects each hazard to cost Montgomery County in an average year, in damage to buildings and crops and in the dollar value it puts on deaths and injuries. Inland flooding leads at $71M a year.
- Inland Flooding$71M56%
- Hurricane$12.5M10%
- Heat Wave$10.9M9%
- Earthquake$8.3M7%
- Cold Wave$6.4M5%
- Tornado$4.3M3%
- Strong Wind$4.3M3%
- Hail$3.2M3%
Of the $126.4M total: buildings $96.8M, people $28.1M, agriculture $1.5M.
All 18 hazards FEMA scores
| Hazard | Expected annual loss | Loss rating | Risk rating | Events on record |
|---|---|---|---|---|
| Inland Flooding | $71.02M | Relatively High | Relatively High | 153 |
| Hurricane | $12.5M | Relatively High | Relatively Moderate | 32 |
| Heat Wave | $10.94M | Relatively High | Relatively High | 91 |
| Earthquake | $8.25M | Relatively Moderate | Relatively Moderate | — |
| Cold Wave | $6.41M | Relatively High | Relatively Moderate | 31 |
| Tornado | $4.34M | Relatively Moderate | Relatively Moderate | 24 |
| Strong Wind | $4.31M | Relatively High | Relatively High | 313 |
| Hail | $3.23M | Relatively High | Relatively High | 151 |
| Winter Weather | $2.37M | Very High | Very High | 229 |
| Lightning | $1.57M | Relatively High | Relatively High | — |
| Drought | $1.2M | Relatively Moderate | Relatively Moderate | 154 |
| Ice Storm | $266K | Relatively Moderate | Relatively Moderate | 43 |
| Wildfire | $13K | Very Low | Very Low | — |
| Landslide | $11K | Relatively Low | Relatively Low | — |
| Coastal Flooding | $218 | Very Low | Very Low | — |
| Avalanche | — | Not Applicable | Not Applicable | — |
| Tsunami | — | Not Applicable | Not Applicable | — |
| Volcanic Activity | — | Not Applicable | Not Applicable | — |
FEMA hazard mitigation grants
Projects FEMA has funded in Montgomery County through its Hazard Mitigation Assistance programs, as OpenFEMA lists them. Grants to towns and cities inside the county count here; statewide grants don’t.
- Funded projects
- 13
- Federal share
- $4M
- Fiscal years
- 1989–2024
By program
- LPDM · Legislative Pre-Disaster Mitigation$1.7M · 5 projects
- HMGP · Hazard Mitigation Grant Program$1.5M · 4 projects
- FMA · Flood Mitigation Assistance$725K · 2 projects
- PDM · Pre-Disaster Mitigation$109K · 2 projects
Most recent projects
FY2024 · LPDM · Obligated$739K
Other Minor Flood Control
Maryland Department of Emergency Management
FY2022 · FMA · Awarded$700K
City of Rockville Flood Resiliency Master Plan
The Mayor and Council of Rockville
FY2022 · LPDM · Obligated$376K
Generators
City of Rockville
FY2016 · PDM · Closed$40K
Local Multijurisdictional Multihazard Mitigation Plan
Montgomery County
FY2014 · HMGP · Closed$8K
Generators
Somerset
FY2010 · LPDM · Closed$68K
Generators
Mayor and Council of Rockville, Maryland
FY2010 · LPDM · Closed$275K
Generators
Mayor & Council of Rockville
FY2010 · LPDM · Closed$224K
Generators
Mayor and Council of Rockville, Maryland
| FY | Project | Recipient | Federal share | Status |
|---|---|---|---|---|
| 2024 | Other Minor Flood ControlLPDM · LPDM-PJ-03-MD-2024-002 | Maryland Department of Emergency Management | $739K | Obligated |
| 2022 | City of Rockville Flood Resiliency Master PlanFMA · EMP-2022-FM-010-0002 | The Mayor and Council of Rockville | $700K | Awarded |
| 2022 | GeneratorsLPDM · LPDM-PJ-03-MD-2022-001 | City of Rockville | $376K | Obligated |
| 2016 | Local Multijurisdictional Multihazard Mitigation PlanPDM · PDMC-PL-03-MD-2016-005 | Montgomery County | $40K | Closed |
| 2014 | GeneratorsHMGP · DR-4170-0012-R | Somerset | $8K | Closed |
| 2010 | GeneratorsLPDM · LPDM-PJ-03-MD-2010-007 | Mayor and Council of Rockville, Maryland | $68K | Closed |
| 2010 | GeneratorsLPDM · LPDM-PJ-03-MD-2010-003 | Mayor & Council of Rockville | $275K | Closed |
| 2010 | GeneratorsLPDM · LPDM-PJ-03-MD-2010-002 | Mayor and Council of Rockville, Maryland | $224K | Closed |
What the money paid for most often
- Generators ×5
- FMA or CRS Plan ×1
- Other Minor Flood Control ×1
- Relocation of Public Structures - Riverine ×1
Hazard mitigation plan
2024 Montgomery County Hazard Mitigation Plan
A multi-jurisdictional plan covering the county and 17 of its municipalities, written alongside the county's Climate Action Plan.
- Adopted
- 2024
- FEMA approval runs to
- June 24, 2029
Frequently Asked Questions
Neighboring counties
About this data
Scores. FEMA’s National Risk Index (December 2025 release) ranks every U.S. county against all the others. A score is a percentile: a risk score of 82 means a higher value than 82% of counties. The risk index is the expected annual loss scaled up for higher social vulnerability and down for stronger community resilience. FEMA groups risk and loss into five ratings by natural breaks, and vulnerability and resilience into national fifths.
Expected annual loss is FEMA’s modeled average yearly loss from 18 natural hazards to buildings (at replacement value), crops and livestock, and people, whose expected deaths and injuries FEMA converts to dollars. It is an average, not a forecast: a low-risk county can still have a bad year.
Vulnerability and resilience. Social vulnerability comes from the U.S. Census Bureau’s Community Resilience Estimates. Community resilience is FEMA’s version of the University of South Carolina’s Baseline Resilience Indicators for Communities (2020), which counts past mitigation spending among its inputs. Vulnerability scores bottom out: 334 of the 3,144 counties scored, 8 of them in Maryland, share the lowest score, 10.6. Population is the 2020 Census count.
Grants are FEMA’s Hazard Mitigation Assistance awards in Maryland that are closed, approved, obligated or awarded: the projects in OpenFEMA’s older project file, which FEMA froze on August 31, 2026, plus the grants FEMA has managed in FEMA GO since fiscal 2020, from HMA Subapplications (both retrieved September 30, 2026). Projects FEMA now lists as withdrawn or denied are left out unless money was obligated to them. Amounts are the federal share obligated. Each grant counts toward the county it serves; 103 statewide grants ($24.1M) count toward none.
FEMA describes the index as one source for risk-reduction decisions, to weigh alongside benefit-cost analysis and local knowledge.
National Risk IndexRisk Index data (OpenFEMA)HMA Subapplications (OpenFEMA)Risk Index FAQ (FEMA, PDF)
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