Lake County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
Very LowComposite Risk Score
National percentile: 33th
Lake County faces very low composite natural disaster risk (NRI Risk Index score 32.6, 33th national percentile), driven primarily by winter weather and ice storm exposure. Expected annual loss across all 18 hazard types is $12M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Lake County is very low, with a National Risk Index score of 32.6 out of 100 — placing it in the 33rd national percentile and among the lowest-risk counties in the country. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in winter weather (heavy snow, blizzards, and hazardous winter conditions) at Medium risk — $266K in expected annual loss and about 19.05 events per year; ice storm (freezing rain that coats surfaces in heavy, damaging ice) at Medium risk — $390K in expected annual loss and about 0.75 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $3M in expected annual loss and about 0.43 events per year. Across all hazards, FEMA estimates $12M in expected annual loss for a population of 11K.
Beyond physical exposure, Lake County has a low social vulnerability rating (how susceptible the population is to harm) and a high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
History supports the rating: Lake County has received 20 federal disaster declarations since 1969, including 8 for flood events and 7 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, and Flooding (flood), declared in August 2024.
Among 66 South Dakota counties, Lake County ranks #24 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Winter Weather | Medium | 19.05 / yr | $266K |
| Ice Storm | Medium | 0.75 / yr | $390K |
| Tornado | Medium | 0.43 / yr | $3M |
| Hail | Low | 5.45 / yr | $570K |
| Cold Wave | Low | 10.21 / yr | $2M |
| Wildfire | Very Low | 0.00 / yr | $65K |
| Drought | Low | 8.00 / yr | $139K |
| Strong Wind | Low | 3.63 / yr | $530K |
| Heat Wave | Very Low | 4.32 / yr | $236K |
| Riverine Flood | Very Low | 0.68 / yr | $4M |
| Landslide | Very Low | 0.06 / yr | $286 |
| Earthquake | Very Low | 0.00 / yr | $36K |
| Lightning | Very Low | 36.11 / yr | $27K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | 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
Lake County has received 20 federal disaster declarations since 1969, most recently Severe Storms, Straight-Line Winds, and Flooding in August 2024. Most frequent causes: Flood (8), Severe Storm (7), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| August 2024 | Flood | Severe Storms, Straight-Line Winds, and Flooding |
| June 2022 | Severe Storm | Severe Storm, Straight-Line Winds, Tornadoes, and Flooding |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| November 2019 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| June 2019 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| May 2011 | Flood | Flooding |
| November 2010 | Severe Storm | Severe Storms and Flooding |
| May 2010 | Flood | Flooding |
| May 2007 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
Showing the 10 most recent of 20 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Lake County?
Lake County has a composite FEMA National Risk Index score of 32.6 out of 100, placing it in the Very Low category and the 33th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Lake County?
The three highest-rated hazards are Winter Weather (Medium, $266K EAL), Ice Storm (Medium, $390K EAL), Tornado (Medium, $3M EAL). These account for most of the county's expected annual losses.
How does Lake County compare to other South Dakota counties?
Lake County ranks #24 of 66 South Dakota counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Lake County had?
FEMA records 20 federal disaster declarations for Lake County since 1969, most often 8 for flood events and 7 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, and Flooding, declared in August 2024.
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. Lake County's $12M EAL is a statistical average, not a guarantee for any specific year or address.