Delta County, Colorado Natural Disaster Risk
FEMA National Risk Index assessment · CO
LowComposite Risk Score
National percentile: 51th
Delta County faces low composite natural disaster risk (NRI Risk Index score 51.3, 51th national percentile), driven primarily by landslide and wildfire exposure. Expected annual loss across all 18 hazard types is $14M.
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 51.3 out of 100 — placing it in the 51st 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.
Most of Delta County's expected losses come from landslide (downhill movement of rock, soil, and debris on unstable slopes) at Medium risk — $93K in expected annual loss and about 0.79 events per year; wildfire (uncontrolled fires that spread across wildland and into communities) at Low risk — $709K in expected annual loss and about 0.00 events per year; and lightning (electrical discharges from storms that ignite fires and cause casualties) at High risk — $712K in expected annual loss and about 58.35 events per year. Across all hazards, FEMA estimates $14M in expected annual loss for a population of 31K.
Beyond physical exposure, Delta County has a high social vulnerability rating (how susceptible the population is to harm) and a 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: Delta County has received 9 federal disaster declarations since 1970, including 3 for flood events and 2 for biological events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 64 Colorado counties, Delta County ranks #20 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Landslide | Medium | 0.79 / yr | $93K |
| Wildfire | Low | 0.00 / yr | $709K |
| Lightning | High | 58.35 / yr | $712K |
| Avalanche | Medium | 0.70 / yr | $311K |
| Riverine Flood | Low | 0.61 / yr | $11M |
| Drought | Medium | 67.69 / yr | $415K |
| Earthquake | Low | 0.00 / yr | $604K |
| Winter Weather | Low | 25.66 / yr | $41K |
| Cold Wave | Very Low | 0.03 / yr | $183K |
| Heat Wave | Very Low | 0.05 / yr | $47K |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
| Ice Storm | Very Low | 0.01 / yr | $8K |
| Strong Wind | Very Low | 0.28 / yr | $79K |
| Tornado | Very Low | 0.03 / yr | $44K |
| Hail | Very Low | 0.14 / yr | $18K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Delta County has received 9 federal disaster declarations since 1970, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (3), Biological (2), Fire (2).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2005 | Coastal Storm | Hurricane Katrina Evacuation |
| July 2004 | Fire | Co-Mcgruder Fire-07/03/2004 |
| June 2002 | Fire | Wildfires |
| July 1984 | Flood | Severe Storms, Mudslides, Landslides & Flooding |
| January 1977 | Drought | Drought |
| July 1973 | Flood | Flooding & Landslides |
| September 1970 | Flood | Heavy Rains & Flooding |
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 51.3 out of 100, placing it in the Low category and the 51th 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 Landslide (Medium, $93K EAL), Wildfire (Low, $709K EAL), Lightning (High, $712K EAL). These account for most of the county's expected annual losses.
How does Delta County compare to other Colorado counties?
Delta County ranks #20 of 64 Colorado counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Delta County had?
FEMA records 9 federal disaster declarations for Delta County since 1970, most often 3 for flood events and 2 for biological 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 $14M EAL is a statistical average, not a guarantee for any specific year or address.