Delta County, Michigan Natural Disaster Risk
FEMA National Risk Index assessment · MI
LowComposite Risk Score
National percentile: 53th
Delta County faces low composite natural disaster risk (NRI Risk Index score 53.1, 53th national percentile), driven primarily by cold wave and hail exposure. Expected annual loss across all 18 hazard types is $15M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Delta County at low composite risk, with a National Risk Index score of 53.1 out of 100 — placing it in the 53rd national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
The county's risk is driven primarily by cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $5M in expected annual loss and about 3.63 events per year; hail (ice stones from severe thunderstorms that damage property and crops) at Medium risk — $885K in expected annual loss and about 0.89 events per year; and lightning (electrical discharges from storms that ignite fires and cause casualties) at Medium risk — $339K in expected annual loss and about 25.14 events per year. Across all hazards, FEMA estimates $15M in expected annual loss for a population of 37K.
Beyond physical exposure, Delta County has a high social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). Higher vulnerability is partly offset by strong community resilience and recovery capacity.
The federal record bears this out: Delta County has received 6 federal disaster declarations since 1977, including 2 for biological events and 1 for hurricane events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 83 Michigan counties, Delta County ranks #41 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | Medium | 3.63 / yr | $5M |
| Hail | Medium | 0.89 / yr | $885K |
| Lightning | Medium | 25.14 / yr | $339K |
| Riverine Flood | Low | 0.43 / yr | $8M |
| Landslide | Very Low | 0.21 / yr | $1K |
| Wildfire | Very Low | 0.00 / yr | $39K |
| Strong Wind | Low | 0.90 / yr | $340K |
| Coastal Flood | Very Low | 0.01 / yr | $8K |
| Winter Weather | Low | 18.69 / yr | $22K |
| Tornado | Very Low | 0.14 / yr | $288K |
| Drought | Very Low | 1.52 / yr | $5K |
| Ice Storm | Very Low | 0.03 / yr | $9K |
| Heat Wave | Very Low | 0.21 / yr | $24K |
| Earthquake | Very Low | 0.00 / yr | $5K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Delta County has received 6 federal disaster declarations since 1977, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Biological (2), Hurricane (1), Freezing (1).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| May 1994 | Freezing | Severe Deep Freeze |
| January 1978 | Snowstorm | Blizzards & Snowstorms |
| March 1977 | Drought | Drought |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Delta County?
Delta County has a composite FEMA National Risk Index score of 53.1 out of 100, placing it in the Low category and the 53th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Delta County?
The three highest-rated hazards are Cold Wave (Medium, $5M EAL), Hail (Medium, $885K EAL), Lightning (Medium, $339K EAL). These account for most of the county's expected annual losses.
How does Delta County compare to other Michigan counties?
Delta County ranks #41 of 83 Michigan counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Delta County had?
FEMA records 6 federal disaster declarations for Delta County since 1977, most often 2 for biological events and 1 for hurricane events. The most recent was Covid-19 Pandemic, declared in March 2020.
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. Delta County's $15M EAL is a statistical average, not a guarantee for any specific year or address.