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The data below is historical (NOAA Storm Events / FEMA), not a live alert. For current warnings and evacuation orders, check the National Weather Service, Ready.gov, or FEMA.gov.

California · FEMA + NOAA + National Risk Index

Alameda County, CA

24 FEMA disaster declarations (1970-2023), with a FEMA National Risk Index rating of Very High. Most common hazard: Severe Storm.

24
FEMA declarations
20
Major disasters
100
NRI risk · Very High
Severe Storm
Top hazard

The verdict

Alameda County has a nationally busy FEMA history: 24 declarations, more than 66% of counties in this registry. But the state comparison tempers that reading: the total is 16% below the California county mean. FEMA's separate National Risk Index places the county in the riskiest 1%; that score models loss and vulnerability rather than counting declarations.

Riskiest 1%
of U.S. counties for FEMA National Risk Index score
Very High
FEMA National Risk Index rating
24
FEMA declarations vs 21 national county avg
568
NFIP flood insurance claims filed

FEMA's National Risk Index and its declaration registry are separate measures. This county's registry includes Major Disaster (DR) and Emergency (EM) records; an EM authorizes a narrower set of federal assistance than a DR.

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How does Alameda County compare?

Alameda County vs. all counties in this dataset

FEMA disaster declarations, all-time

24 Top 34% higher than 66% of 3,266 counties

This county 0 90 all U.S. counties FEMA tracks, bucketed by value

Each bar is a band; taller bars hold more counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source FEMA Disaster Declarations Summaries v2 · 2026-08-03

Alameda County's FEMA Risk Index score

FEMA National Risk Index composite score vs. the California county average

0/100100/100California avg89/10099.8/100
FEMA National Risk Index composite score vs. the California county average

What does Alameda County's hazard record show?

Reading the federal records together

FEMA's NFIP table contains a substantial paid-claim history for this county: 568 claims and $4.4M in payments. PlainHazard labels 500 or more claims a heavy registry record; that is a reporting bucket, not an official FEMA risk grade. The average paid claim was $7.8K. NFIP totals exclude uninsured flood losses and do not measure how many properties currently carry a policy.

Start with the state benchmark: a California county averages 28.5 federal declaration records, while Alameda County has 24. The gap is 16% below that mean. Fewer entries indicate a quieter history of recorded federal actions, not immunity from a hazard and not a prediction about what happens next.

FEMA National Risk Index

This county sits among the highest-risk counties nationally on FEMA's National Risk Index, a composite score of 99.8/100 (Very High). Expected Annual Loss is rated Very High (roughly $1.9B in annualized losses). Social vulnerability reads Relatively Low and community resilience Very High, both critical modifiers of realized harm here. Of the 18 hazards FEMA models, Earthquake stands out as the sharpest exposure here, rated Very High. FEMA's modeled frequency puts that hazard at roughly once every 7 years here.

Declaration frequency

Nationally, Alameda County's 24 FEMA records form a high-volume history; within California, however, the count is 16% below the county mean. 20 entries carry the Major Disaster classification. The largest incident group is Severe Storm, appearing 8 times. The full 53-year record averages 0.5 declarations annually. A DR label alone does not say whether Individual Assistance, Public Assistance, or both followed.

69 /100

Historical Activity Index

High historical activity

Alameda County, CA · PlainHazard-derived composite from federal records

This 0–100 index is an explicit PlainHazard composite from FEMA declaration history only on the county surface (this DB has no county-level NOAA damage row) . It is not FEMA's National Risk Index, not a forecast, and not a safety, insurance, or preparedness rating. Open the calculator · Methodology

FEMA Declarations (1953–present) High
17/30

24 OpenFEMA declarations, full ingest window (1.2x national county average)

County Disaster Density Moderate
11/25

24 declarations (0.8x state county average of 29)

Major Disaster Share Very High
21/25

20 of 24 declarations are major disasters (83%)

Hazard Diversity Very High
20/20

9 different disaster types declared in Alameda County

Historical Declaration Activity

Activity Band

High

vs. California Avg

-16%

State avg: 28.5

vs. National Avg

+16%

National avg: 20.7

Avg Per Year

0.5

Over 53 years

FEMA NRI 8-hazard radar - Alameda County

Alameda County NRI risk profile 8-axis FEMA National Risk Index radar showing per-hazard scores for Earthquake 92, Flood 92, Hurricane 0, Tornado 48, Wildfire 70, Drought 48, Heat Wave 70, Winter Storm 8. The simple mean of these eight displayed scores is 54 of 100. Earthquake Flood Hurricane Tornado Wildfire Drought Heat Wave Winter Storm 54 8-hazard mean
Alameda County NRI risk profile FIPS 06001 · displayed-hazard mean 54/100
How to read this radar

Each axis: NRI risk rating (Very Low-Very High) on a 0-100 scale. Rounder = broad exposure; spiky = one or two hazards dominate.

FEMA Records

24

Above median

Major Disaster share

83%

Mostly major

NRI risk score

100

Very High

Source: FEMA National Risk Index FEMA National Risk Index Per-county per-hazard ratings, December 2025 release

How often does each hazard strike Alameda County?

FEMA's National Risk Index models a historical event count and an annualized frequency for each hazard type. Most hazards are expressed as modeled occurrences per year; FEMA expresses drought and heat-wave frequency as event-days per year. These modeled frequencies are not forecasts.

Hazard NRI Risk Rating Recurrence
Earthquake Very High roughly once every 7 years
Landslide Relatively High an average of 25 times per year
Riverine Flooding Very High an average of 2.3 times per year
Wildfire Relatively High roughly once every 173 years
Heat Wave Relatively High 7.1 modeled event-days per year
Coastal Flooding Relatively High roughly once every 1 years
Drought Relatively Moderate 58 modeled event-days per year
Volcanic Activity Very Low roughly once every 3,333 years
Tornado Relatively Moderate roughly once every 11 years
Tsunami Relatively Low roughly once every 3 years
Lightning Relatively Low an average of 4.5 times per year
Hail Relatively Low roughly once every 25 years
Strong Wind Very Low roughly once every 24 years
Avalanche Very Low roughly once every 100 years
Winter Weather Very Low roughly once every 1 years

Source: FEMA National Risk Index FEMA National Risk Index Modeled annualized frequency; drought and heat wave use event-days/year, December 2025 release

Disaster Types

Severe Storm 8
Flood 7
Biological 2
Fire 2
Hurricane 1
Freezing 1
Earthquake 1
Coastal Storm 1
Drought 1

What Severe Storm declarations mean here

Severe Storm is the most frequent declaration type on Alameda County's record, 33% of its declarations. In FEMA's vocabulary this covers convective weather: thunderstorm straight-line winds, large hail, and the multi-day outbreaks that often carry embedded tornadoes. Activity is heaviest in spring and summer, though the season varies by region.

These events behave differently from a hurricane on paper. Damage tends to be distributed along a storm track rather than concentrated on a coastline, and a declaration typically follows an outbreak that crossed several counties over a few days, not a single point of impact. Because the qualifying threshold is the cost of uninsured public and individual losses rather than storm intensity, two similar storms can produce a declaration in one year and none in another.

Declaration counts describe past federal action. They are a record of what was declared, not a forecast of future hazard probability.

Declaration Types

What DR / EM / FM mean

FEMA categorizes declarations as Major Disasters (DR), Emergencies (EM), or Fire Management Assistance (FM).

Major Disaster - 20 83.3%

of all 24 declarations

Emergency - 4 16.7%

of all 24 declarations

FEMA Declarations Timeline

Year Declarations
2023 3
2020 2
2017 3
2006 2
2005 1
1998 1
1997 1
1995 2
1992 1
1991 1
1990 1
1986 1
1983 1
1982 1
1977 1
Show 1 earlier declaration years
1970 2

Disaster Declarations

How the 24 FEMA declarations break into federal action codes (DR / EM / FM). Same DISTINCT grain as the table below.

Download these 24 declarations as CSV . FEMA source data is public domain; our derived presentation is CC0.

DR# Title Type Incident Date
4699 SEVERE WINTER STORMS, STRAIGHT-LINE WINDS, FLOODING, LANDSLIDES, AND MUDSLIDES DR Severe Storm 2023-04-03
4683 SEVERE WINTER STORMS, FLOODING, LANDSLIDES, AND MUDSLIDES DR Flood 2023-01-14
3591 SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES EM Flood 2023-01-09
4482 COVID-19 PANDEMIC DR Biological 2020-03-22
3428 COVID-19 EM Biological 2020-03-13
4308 SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES DR Flood 2017-04-01
4305 SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES DR Flood 2017-03-16
4301 SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES DR Severe Storm 2017-02-14
1646 SEVERE STORMS, FLOODING, LANDSLIDES, AND MUDSLIDES DR Severe Storm 2006-06-05
1628 SEVERE STORMS, FLOODING, MUDSLIDES, AND LANDSLIDES DR Severe Storm 2006-02-03
3248 HURRICANE KATRINA EVACUATION EM Hurricane 2005-09-13
1203 SEVERE WINTER STORMS AND FLOODING DR Severe Storm 1998-02-09
1155 SEVERE STORMS, FLOODING, MUD AND LANDSLIDES DR Severe Storm 1997-01-04
1046 SEVERE WINTER STORMS, FLOODING LANDSLIDES, MUD FLOW DR Severe Storm 1995-03-12
1044 SEVERE WINTER STORMS, FLOODING, LANDSLIDES, MUD FLOWS DR Severe Storm 1995-01-10
919 OAKLAND HILLS FIRE DR Fire 1991-10-22
894 SEVERE FREEZE DR Freezing 1991-02-11
845 LOMA PRIETA EARTHQUAKE DR Earthquake 1989-10-18
758 SEVERE STORMS & FLOODING DR Flood 1986-02-21
677 COASTAL STORMS, FLOODS, SLIDES & TORNADOES DR Coastal Storm 1983-02-09
Show 4 earlier declaration records
DR# Title Type Incident Date
651 SEVERE STORMS, FLOOD, MUDSLIDES & HIGH TIDE DR Flood 1982-01-07
3023 DROUGHT EM Drought 1977-01-20
295 FOREST & BRUSH FIRES DR Fire 1970-09-29
283 SEVERE STORMS & FLOODING DR Flood 1970-02-16

Storm Events in California

Statewide NOAA context only. PlainHazard does not currently attribute these state totals to Alameda County.

Storm Type Events Fatalities Injuries Property Damage
High Wind 4,070 13 27 $228.2M
Flood 3,132 26 25 $985.1M
Heavy Snow 1,814 6 0 $1.6M
Dense Fog 1,605 52 148 $2.8M
Drought 1,421 0 0 $0

Source: NOAA Storm Events Database NOAA Storm Events Database State-level aggregated data, 2015-2025

NFIP Flood Insurance Claims

Total Claims

568

Total Paid

$4.4M

Avg Per Claim

$7.8K

Source: FEMA National Flood Insurance Program (NFIP) OpenFEMA Claims Data FEMA National Flood Insurance Program (NFIP) OpenFEMA Claims Data

FEMA National Risk Index

Overall Risk

Very High

Score: 99.8/100

Expected Annual Loss

Very High

$1.9B/year

Social Vulnerability

Relatively Low

Community Resilience

Very High

Hazard Risk Breakdown

Earthquake Very High
Landslide Relatively High
Riverine Flooding Very High
Wildfire Relatively High
Heat Wave Relatively High
Coastal Flooding Relatively High
Drought Relatively Moderate
Volcanic Activity Very Low
Tornado Relatively Moderate
Tsunami Relatively Low
Lightning Relatively Low
Hail Relatively Low
Strong Wind Very Low
Avalanche Very Low
Winter Weather Very Low
Cold Wave No Rating

Source: FEMA National Risk Index (NRI) FEMA National Risk Index (NRI) Ratings reflect relative scores among all US counties. Data: hazards.fema.gov/nri

The model's sharpest exposure here: Earthquake

Earthquake is the model's clearest example of a hazard with no season and no warning. Its expected loss is driven less by how often shaking occurs than by how much of the building stock predates modern seismic codes, so exposure can be high in places where nothing has happened for a long time.

Worth noting for Alameda County: the model and the federal record do NOT point at the same hazard. Earthquake carries the highest modeled rating (Very High), while the county's declaration history is led by Severe Storm. That is not a contradiction, the two measure genuinely different things. Declarations record federal ACTION, which requires damage costly enough to exceed state and local capacity; the Risk Index models EXPECTED annual loss across all 18 hazards whether or not any declaration ever followed. A hazard can be the county's largest modeled exposure and never once have driven a declaration.

National Risk Index ratings are modeled estimates of expected annual loss, not predictions of what will happen in any given year.

Data-matched county comparisons

Alameda County's closest FEMA peer: Blue Earth County, MN

Comparisons use published FEMA declaration fields plus the National Risk Index composite for Alameda County. Record similarity, not a safety rating.

How these peers are chosen

Cohort: Published U.S. county equivalents outside the source state or territory. Each metric keeps six ETL candidates; three unique destinations are shown after de-duplicating across axes. Declaration-volume ranking combines count and Major-disaster share and prefers a different leading incident type; Major-share ranks the Major fraction adjusted for volume; NRI ranks the modeled composite score only.

Retained FEMA snapshot feed for Alameda County - capture-dated entries only.

Further reading for this county

Understanding disaster data

Alameda County's NFIP claims file (568 claims) and FEMA declaration history measure different federal records - this guide separates them from modeled NRI risk.

More PlainHazard guides

Frequently Asked Questions

What is the most common disaster type in Alameda County?
The most common disaster type in Alameda County is Severe Storm, with 8 declarations. Other disaster types include Flood (7), Biological (2), Fire (2).
How does Alameda County's FEMA declaration record compare with the California average?
The typical California county has 28.5 FEMA declaration records; Alameda County has 24, or 16% fewer. Against the national county mean of 20.7, this county's total is 16% higher. The comparison is historical and says nothing about the probability of a future event.
How many major FEMA disaster declarations has Alameda County received?
Alameda County has received 20 major disaster declarations, representing 83% of all 24 disaster declarations.
How many flood insurance claims has Alameda County filed?
Alameda County has 568 National Flood Insurance Program (NFIP) claims totaling $4.4M in payments, with an average of $7.8K per claim.
What was the worst year for disasters in Alameda County?
The most active year for disaster declarations in Alameda County was 2017, with 3 declarations. The county has FEMA disaster data spanning 1970 to 2023.
What is the FEMA National Risk Index score for Alameda County?
According to the FEMA National Risk Index, Alameda County, California has an overall risk score of 99.8 out of 100 (Very High). Social vulnerability here rates Relatively Low, while community resilience comes in at Very High. The Expected Annual Loss (EAL) score is Very High, representing $1.9B in annualized losses.
Which natural hazard poses the greatest risk to Alameda County?
Based on FEMA NRI data, the highest-risk natural hazard in Alameda County is Earthquake (risk rating: Very High). Other significant hazards include Landslide (Relatively High) and Riverine Flooding (Very High). FEMA's modeled event frequency puts earthquake here at roughly once every 7 years. The underlying methodology weighs historical event frequency against exposed assets and community vulnerability.
Data Sources & Methodology

Disaster declaration data comes from the FEMA OpenFEMA Disaster Declarations Summaries v2 API, which includes all federally declared disasters, emergencies, and fire management assistance grants.

Storm event data is sourced from the NOAA Storm Events Database (2015-2025), which tracks significant weather events including thunderstorms, tornadoes, floods, and winter storms.

Flood insurance data comes from the FEMA National Flood Insurance Program (NFIP) OpenFEMA claims dataset.

This data is provided for informational purposes only. FEMA disaster declarations represent federal response actions and may not capture all local emergencies or weather events.

What this means for Alameda County

Against a California county mean of 29 declarations, Alameda County, CA records 24, or 16% fewer. PlainHazard classifies that historical total as high activity.

  • Major Disaster is the largest group (20 of 24) in a declaration history that remains below its state benchmark; frequency here is not a forecast. California overview
  • Nationally the county exceeds 66% of recorded county totals, but its own California benchmark is higher. The ranking keeps those two contexts separate. Most-disaster rankings
  • The large NFIP claims file and FEMA declaration history measure different federal records; the guide explains where they overlap and where they do not. Disaster-data guide

A below-average federal record is not a safety guarantee. Use National Weather Service alerts and local emergency-management notices for present conditions, not this historical comparison.

All federal data sources used on this page
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainHazard Editorial

Verify with FEMA → · Verify with FEMA NRI → · Verify with NOAA →

Every figure on PlainHazard is rendered directly from FEMA federal disaster data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or national statistics report, the data & editorial changelog, or report a data error.