Alameda County, California: hazard history

FEMA declared 24 disasters that named Alameda County between 1970 and 2023.

Most recent declarations

• DR-4699 2023 · Severe Storm · Severe Winter Storms, Straight-line Winds, Flooding, Landslides, And Mudslides
• EM-3591 2023 · Flood · Severe Winter Storms, Flooding, And Mudslides
• DR-4683 2022 · Flood · Severe Winter Storms, Flooding, Landslides, And Mudslides
• EM-3428 2020 · Biological · Covid-19
• DR-4482 2020 · Biological · Covid-19 Pandemic
• DR-4308 2017 · Flood · Severe Winter Storms, Flooding, And Mudslides
• DR-4305 2017 · Flood · Severe Winter Storms, Flooding, And Mudslides
• DR-4301 2017 · Severe Storm · Severe Winter Storms, Flooding, And Mudslides
• DR-1646 2006 · Severe Storm · Severe Storms, Flooding, Landslides, And Mudslides
• DR-1628 2005 · Severe Storm · Severe Storms, Flooding, Mudslides, And Landslides

Not counted above: 34 statewide declarations, which covered every county in California. A declaration is a decision to send federal help, not a measure of how bad an event was. Records run from 1953. Source: FEMA OpenFEMA Disaster Declarations Summaries.

Records start in 1996. Damage is NOAA's estimate at the time, in nominal dollars, and is often rounded; it is not insurance claims data. A storm that crossed two NOAA zones in this county is recorded, and counted, once per zone. A storm filed against a forecast zone is counted in every county that zone covers, with the whole storm's damage; do not add these figures across counties.

NOAA storm event records in Alameda County each year. The busiest year was 2019, with 90 records.

Years with no record are left out of the table, not shown as zero.

Costliest records

1. Debris Flow · Apr 6, 2006$11.0M
   NOAA name: NWS forecast zone · NOAA record 5497356
2. Flood · Dec 31, 2005$8.8M
   NOAA name: Alameda County · NOAA record 5482520
3. Flood · Jan 1, 2006$8.8M
   NOAA name: Alameda County · NOAA record 5486534
4. Hail · Jan 19, 2017$5.0M
   NOAA name: Alameda County · NOAA record 675603
5. High Wind · Oct 13, 2009$2.5M
   NOAA name: NWS forecast zone · NOAA record 199983

Deadliest records

1. Cold/Wind Chill · Dec 2, 20222 deaths
   NOAA name: NWS forecast zone · NOAA record 1069470
2. Heavy Rain · Jan 11, 19981 death
   NOAA name: Alameda County · NOAA record 5636121
3. Heat · Jul 25, 20071 death
   NOAA name: NWS forecast zone · NOAA record 38087
4. Heavy Rain · Nov 1, 20081 death
   NOAA name: Alameda County · $15K damage · NOAA record 142855
5. Heat · Jun 27, 20091 death
   NOAA name: NWS forecast zone · 1 injury · NOAA record 182325

Each line is one NOAA record, linked to its page at NOAA. One large storm can appear more than once if NOAA recorded it in several zones of this county. Dollars are nominal.

The National Flood Insurance Program paid $4.6M on 570 claims in Alameda County from 1978 to 2024.

A count of claims, not a rate: NFIP publishes no count of insured homes beside it, and most flood damage is uninsured. Nominal dollars. Records run from 1978 to 2024; claims filed without a county code are not on any county page. Source: FEMA OpenFEMA FIMA NFIP Redacted Claims.

A hazard vulnerability analysis rates each hazard for probability, impact, preparedness and response. Probability is the one column the county’s federal record can fill — NCEI storm events from 1996 to 2026 and FEMA declarations naming the county — and this is what it says for a facility here, on the 0–3 scale of the all-hazards structure surveyors expect. The other six columns are the facility’s own judgment about its building, and Calchis leaves them blank.

A dash means the record does not speak to that hazard; it is not a zero. Whether a finished document satisfies the CMS Emergency Preparedness Rule is the facility’s finding and its surveyor’s. Complete the HVA for a facility in Alameda County — the technological, human and hazardous-materials rows, the six facility columns, the approval and the printed document — or read the sample analysis on that page first.

• Every figure is counted from public federal records held by Calchis: NOAA NCEI Storm Events, FEMA OpenFEMA Disaster Declarations, and FEMA NFIP claims. Nothing is modeled or estimated.
• NOAA files some events against a county and others against an NWS forecast zone, and publishes a code for both. Records are counted as Alameda County by that code — county records by the county's own FIPS code, zone records through the National Weather Service's published list of which counties each zone covers. No name matching is involved. Of 602 records, 234 were filed against this county and 368 against a forecast zone covering it. A zone storm is counted in every county its zone covers, and its damage figure is the whole storm's, not this county's share — NOAA does not publish that split. So these figures describe this county; they must not be added up across counties. Left out: 29% of California's NOAA records, which are marine zones or zones NWS does not map to a county.
• Counts last rebuilt from the source records on Sep 15, 2026.