LaSalle County, Illinois Natural Disaster Risk
FEMA National Risk Index assessment · IL
MediumComposite Risk Score
National percentile: 86th
LaSalle County faces medium composite natural disaster risk (NRI Risk Index score 86.1, 86th national percentile), driven primarily by cold wave and riverine flood exposure. Expected annual loss across all 18 hazard types is $61M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in LaSalle County is medium, with a National Risk Index score of 86.1 out of 100 — placing it in the 86th national percentile and near the national midpoint 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 High risk — $15M in expected annual loss and about 5.26 events per year; riverine flood (rivers and streams overflowing their banks after heavy rain or snowmelt) at Medium risk — $33M in expected annual loss and about 2.00 events per year; and drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $1M in expected annual loss and about 7.80 events per year. Across all hazards, FEMA estimates $61M in expected annual loss for a population of 110K.
Beyond physical exposure, LaSalle County 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 federal record bears this out: LaSalle County has received 20 federal disaster declarations since 1967, including 6 for flood events and 5 for snowstorm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 102 Illinois counties, LaSalle County ranks #16 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 5.26 / yr | $15M |
| Riverine Flood | Medium | 2.00 / yr | $33M |
| Drought | Medium | 7.80 / yr | $1M |
| Strong Wind | High | 5.94 / yr | $2M |
| Tornado | Medium | 1.08 / yr | $5M |
| Earthquake | Low | 0.00 / yr | $2M |
| Lightning | Medium | 44.02 / yr | $527K |
| Winter Weather | Medium | 15.05 / yr | $131K |
| Heat Wave | Low | 4.37 / yr | $909K |
| Landslide | Low | 0.21 / yr | $5K |
| Hail | Low | 4.10 / yr | $412K |
| Ice Storm | Medium | 0.70 / yr | $149K |
| Hurricane | Very Low | 0.01 / yr | $15K |
| Wildfire | Very Low | 0.00 / yr | $8K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
LaSalle County has received 20 federal disaster declarations since 1967, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (6), Snowstorm (5), Severe Storm (4).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| November 2013 | Tornado | Severe Storms, Straight-Line Winds, and Tornadoes |
| May 2013 | Flood | Severe Storms, Straight-Line Winds, and Flooding |
| March 2011 | Snowstorm | Severe Winter Storm and Snowstorm |
| October 2008 | Severe Storm | Severe Storms and Flooding |
| September 2007 | Severe Storm | Severe Storms and Flooding |
| December 2006 | Snowstorm | Snow |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| April 2004 | Severe Storm | Severe Storms and Tornadoes |
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 LaSalle County?
LaSalle County has a composite FEMA National Risk Index score of 86.1 out of 100, placing it in the Medium category and the 86th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in LaSalle County?
The three highest-rated hazards are Cold Wave (High, $15M EAL), Riverine Flood (Medium, $33M EAL), Drought (Medium, $1M EAL). These account for most of the county's expected annual losses.
How does LaSalle County compare to other Illinois counties?
LaSalle County ranks #16 of 102 Illinois counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has LaSalle County had?
FEMA records 20 federal disaster declarations for LaSalle County since 1967, most often 6 for flood events and 5 for snowstorm 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. LaSalle County's $61M EAL is a statistical average, not a guarantee for any specific year or address.