Merced County, California Natural Disaster Risk
FEMA National Risk Index assessment · CA
HighComposite Risk Score
National percentile: 97th
Merced County faces high composite natural disaster risk (NRI Risk Index score 96.9, 97th national percentile), driven primarily by drought and earthquake exposure. Expected annual loss across all 18 hazard types is $205M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Merced County is high, with a National Risk Index score of 96.9 out of 100 — placing it in the 97th national percentile and in the upper tier of natural-disaster risk nationally. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Merced County's expected losses come from drought (extended dry periods that stress water supplies and agriculture) at Very High risk — $70M in expected annual loss and about 74.16 events per year; earthquake (ground shaking from sudden movement along geologic faults) at High risk — $62M in expected annual loss and about 0.09 events per year; and heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at High risk — $10M in expected annual loss and about 10.06 events per year. Across all hazards, FEMA estimates $205M in expected annual loss for a population of 281K.
Beyond physical exposure, Merced County has a high social vulnerability rating (how susceptible the population is to harm) and a very low community resilience rating (its capacity to prepare for and recover from disasters). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
The federal record bears this out: Merced County has received 19 federal disaster declarations since 1969, including 6 for severe storm events and 5 for flood events. The most recent was Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides (severe storm), declared in April 2023.
Among 58 California counties, Merced County ranks #22 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | Very High | 74.16 / yr | $70M |
| Earthquake | High | 0.09 / yr | $62M |
| Heat Wave | High | 10.06 / yr | $10M |
| Riverine Flood | High | 1.86 / yr | $59M |
| Wildfire | Medium | 0.01 / yr | $2M |
| Lightning | High | 6.60 / yr | $739K |
| Hail | Low | 0.14 / yr | $403K |
| Landslide | Very Low | 14.94 / yr | $2K |
| Volcanic Activity | Very Low | 0.00 / yr | $10 |
| Tornado | Low | 0.22 / yr | $322K |
| Strong Wind | Low | 0.04 / yr | $151K |
| Winter Weather | Very Low | 0.24 / yr | $14K |
| Avalanche | Very Low | 0.01 / yr | $1 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Cold Wave | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Ice Storm | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Merced County has received 19 federal disaster declarations since 1969, most recently Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in April 2023. Most frequent causes: Severe Storm (6), Flood (5), Freezing (3).
| Declared | Type | Disaster |
|---|---|---|
| April 2023 | Severe Storm | Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides |
| March 2023 | Flood | Severe Winter Storms, Flooding, Landslides, and Mudslides |
| January 2023 | Flood | Severe Winter Storms, Flooding, Landslides, and Mudslides |
| January 2023 | Flood | Severe Winter Storms, Flooding, and Mudslides |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| April 2017 | Flood | Severe Winter Storms, Flooding, and Mudslides |
| February 2017 | Severe Storm | Severe Winter Storms, Flooding, and Mudslides |
| March 2007 | Freezing | Severe Freeze |
| June 2006 | Severe Storm | Severe Storms, Flooding, Landslides, and Mudslides |
Showing the 10 most recent of 19 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Merced County?
Merced County has a composite FEMA National Risk Index score of 96.9 out of 100, placing it in the High category and the 97th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Merced County?
The three highest-rated hazards are Drought (Very High, $70M EAL), Earthquake (High, $62M EAL), Heat Wave (High, $10M EAL). These account for most of the county's expected annual losses.
How does Merced County compare to other California counties?
Merced County ranks #22 of 58 California counties for overall natural disaster risk, with a high rating.
How many federally declared disasters has Merced County had?
FEMA records 19 federal disaster declarations for Merced County since 1969, most often 6 for severe storm events and 5 for flood events. The most recent was Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared in April 2023.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Merced County's $205M EAL is a statistical average, not a guarantee for any specific year or address.