St. Tammany Parish, Louisiana Natural Disaster Risk
FEMA National Risk Index assessment · LA
HighComposite Risk Score
National percentile: 97th
St. Tammany Parish faces high composite natural disaster risk (NRI Risk Index score 96.6, 97th national percentile), driven primarily by hurricane and heat wave exposure. Expected annual loss across all 18 hazard types is $249M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in St. Tammany Parish is high, with a National Risk Index score of 96.6 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.
Risk here concentrates in hurricane (tropical cyclones bringing extreme wind, rain, and storm surge) at Very High risk — $143M in expected annual loss and about 0.23 events per year; heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at Medium risk — $8M in expected annual loss and about 16.11 events per year; and lightning (electrical discharges from storms that ignite fires and cause casualties) at High risk — $2M in expected annual loss and about 84.65 events per year. Across all hazards, FEMA estimates $249M in expected annual loss for a population of 264K.
Beyond physical exposure, St. Tammany Parish has a low 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). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The county's disaster history tells the same story: St. Tammany Parish has received 50 federal disaster declarations since 1965, including 29 for hurricane events and 7 for flood events. The most recent was Tropical Storm Arthur (tropical storm), declared in June 2026.
Among 64 Louisiana counties, St. Tammany Parish ranks #4 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Hurricane | Very High | 0.23 / yr | $143M |
| Heat Wave | Medium | 16.11 / yr | $8M |
| Lightning | High | 84.65 / yr | $2M |
| Riverine Flood | High | 2.32 / yr | $70M |
| Cold Wave | High | 1.09 / yr | $9M |
| Wildfire | Medium | 0.00 / yr | $1M |
| Hail | Medium | 1.95 / yr | $2M |
| Tornado | Medium | 1.03 / yr | $6M |
| Coastal Flood | High | 3.70 / yr | $3M |
| Strong Wind | Medium | 1.61 / yr | $1M |
| Drought | Medium | 18.53 / yr | $988K |
| Winter Weather | Medium | 1.07 / yr | $208K |
| Ice Storm | Medium | 0.53 / yr | $370K |
| Earthquake | Low | 0.00 / yr | $724K |
| Landslide | Very Low | 0.12 / yr | $596 |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
St. Tammany Parish has received 50 federal disaster declarations since 1965, most recently Tropical Storm Arthur in June 2026. Most frequent causes: Hurricane (29), Flood (7), Coastal Storm (4).
| Declared | Type | Disaster |
|---|---|---|
| June 2026 | Tropical Storm | Tropical Storm Arthur |
| January 2026 | Winter Storm | Severe Winter Storm |
| September 2024 | Hurricane | Hurricane Francine |
| September 2024 | Hurricane | Tropical Storm Francine |
| September 2021 | Coastal Storm | Tropical Storm Nicholas |
| August 2021 | Hurricane | Hurricane Ida |
| August 2021 | Hurricane | Tropical Storm Ida |
| March 2021 | Severe Ice Storm | Severe Winter Storms |
| February 2021 | Severe Ice Storm | Severe Winter Storm |
| January 2021 | Hurricane | Hurricane Zeta |
Showing the 10 most recent of 50 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for St. Tammany Parish?
St. Tammany Parish has a composite FEMA National Risk Index score of 96.6 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 St. Tammany Parish?
The three highest-rated hazards are Hurricane (Very High, $143M EAL), Heat Wave (Medium, $8M EAL), Lightning (High, $2M EAL). These account for most of the county's expected annual losses.
How does St. Tammany Parish compare to other Louisiana counties?
St. Tammany Parish ranks #4 of 64 Louisiana counties for overall natural disaster risk, with a high rating.
How many federally declared disasters has St. Tammany Parish had?
FEMA records 50 federal disaster declarations for St. Tammany Parish since 1965, most often 29 for hurricane events and 7 for flood events. The most recent was Tropical Storm Arthur, declared in June 2026.
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. St. Tammany Parish's $249M EAL is a statistical average, not a guarantee for any specific year or address.