St. Lawrence County, New York Natural Disaster Risk
FEMA National Risk Index assessment · NY
LowComposite Risk Score
National percentile: 78th
St. Lawrence County faces low composite natural disaster risk (NRI Risk Index score 77.9, 78th national percentile), driven primarily by cold wave and ice storm exposure. Expected annual loss across all 18 hazard types is $32M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in St. Lawrence County is low, with a National Risk Index score of 77.9 out of 100 — placing it in the 78th 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 4.63 events per year; ice storm (freezing rain that coats surfaces in heavy, damaging ice) at High risk — $606K in expected annual loss and about 0.66 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at High risk — $274K in expected annual loss and about 19.69 events per year. Across all hazards, FEMA estimates $32M in expected annual loss for a population of 108K.
Beyond physical exposure, St. Lawrence County has a high 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). Higher vulnerability is partly offset by strong community resilience and recovery capacity.
History supports the rating: St. Lawrence County has received 19 federal disaster declarations since 1991, including 6 for snowstorm events and 3 for flood events. The most recent was Remnants of Tropical Storm Debby (tropical storm), declared in September 2024.
Among 62 New York counties, St. Lawrence County ranks #25 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | Medium | 4.63 / yr | $5M |
| Ice Storm | High | 0.66 / yr | $606K |
| Winter Weather | High | 19.69 / yr | $274K |
| Earthquake | Low | 0.00 / yr | $3M |
| Riverine Flood | Medium | 0.96 / yr | $22M |
| Lightning | Medium | 23.71 / yr | $547K |
| Landslide | Low | 2.11 / yr | $10K |
| Hurricane | Low | 0.01 / yr | $158K |
| Heat Wave | Very Low | 1.28 / yr | $169K |
| Strong Wind | Low | 0.54 / yr | $294K |
| Wildfire | Very Low | 0.00 / yr | $15K |
| Tornado | Very Low | 0.10 / yr | $285K |
| Avalanche | Very Low | 0.01 / yr | $22 |
| Hail | Very Low | 0.34 / yr | $6K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
St. Lawrence County has received 19 federal disaster declarations since 1991, most recently Remnants of Tropical Storm Debby in September 2024. Most frequent causes: Snowstorm (6), Flood (3), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| September 2024 | Tropical Storm | Remnants of Tropical Storm Debby |
| August 2024 | Flood | Severe Storm, Tornadoes, and Flooding |
| March 2023 | Snowstorm | Severe Winter Storm and Snowstorm |
| November 2022 | Winter Storm | Severe Winter Storm and Snowstorm |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| November 2017 | Flood | Flooding |
| December 2014 | Snowstorm | Severe Winter Storm, Snowstorm, and Flooding |
| October 2012 | Hurricane | Hurricane Sandy |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
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 St. Lawrence County?
St. Lawrence County has a composite FEMA National Risk Index score of 77.9 out of 100, placing it in the Low category and the 78th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in St. Lawrence County?
The three highest-rated hazards are Cold Wave (Medium, $5M EAL), Ice Storm (High, $606K EAL), Winter Weather (High, $274K EAL). These account for most of the county's expected annual losses.
How does St. Lawrence County compare to other New York counties?
St. Lawrence County ranks #25 of 62 New York counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has St. Lawrence County had?
FEMA records 19 federal disaster declarations for St. Lawrence County since 1991, most often 6 for snowstorm events and 3 for flood events. The most recent was Remnants of Tropical Storm Debby, declared in September 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. St. Lawrence County's $32M EAL is a statistical average, not a guarantee for any specific year or address.