Portage County, Wisconsin Natural Disaster Risk
FEMA National Risk Index assessment · WI
LowComposite Risk Score
National percentile: 63th
Portage County faces low composite natural disaster risk (NRI Risk Index score 62.7, 63th national percentile), driven primarily by cold wave and hail exposure. Expected annual loss across all 18 hazard types is $36M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Portage County is low, with a National Risk Index score of 62.7 out of 100 — placing it in the 63rd 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 — $9M in expected annual loss and about 8.16 events per year; hail (ice stones from severe thunderstorms that damage property and crops) at Medium risk — $2M in expected annual loss and about 2.63 events per year; and lightning (electrical discharges from storms that ignite fires and cause casualties) at Medium risk — $867K in expected annual loss and about 33.01 events per year. Across all hazards, FEMA estimates $36M in expected annual loss for a population of 70K.
Beyond physical exposure, Portage County has a very 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.
History supports the rating: Portage County has received 12 federal disaster declarations since 1973, including 4 for severe storm events and 3 for flood events. The most recent was Covid-19 Pandemic (biological), declared in April 2020.
Among 72 Wisconsin counties, Portage County ranks #37 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | Medium | 8.16 / yr | $9M |
| Hail | Medium | 2.63 / yr | $2M |
| Lightning | Medium | 33.01 / yr | $867K |
| Tornado | Medium | 0.42 / yr | $4M |
| Riverine Flood | Low | 0.46 / yr | $18M |
| Strong Wind | Medium | 2.66 / yr | $1M |
| Winter Weather | Low | 15.63 / yr | $121K |
| Landslide | Very Low | 0.13 / yr | $2K |
| Heat Wave | Low | 1.42 / yr | $414K |
| Ice Storm | Low | 0.21 / yr | $63K |
| Wildfire | Very Low | 0.00 / yr | $26K |
| Drought | Very Low | 0.29 / yr | $4K |
| Earthquake | Very Low | 0.00 / yr | $34K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.01 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Portage County has received 12 federal disaster declarations since 1973, most recently Covid-19 Pandemic in April 2020. Most frequent causes: Severe Storm (4), Flood (3), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| August 2019 | Flood | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| October 2010 | Severe Storm | Severe Storms and Flooding |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| June 2004 | Severe Storm | Severe Storms and Flooding |
| September 2002 | Tornado | Severe Storms, Tornadoes and Flooding |
| July 2002 | Severe Storm | Severe Storms and Flooding |
| May 2001 | Flood | Flooding, Severe Storms and Tornadoes |
| July 1993 | Severe Storm | Severe Storms, Tornadoes & Flooding |
Showing the 10 most recent of 12 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Portage County?
Portage County has a composite FEMA National Risk Index score of 62.7 out of 100, placing it in the Low category and the 63th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Portage County?
The three highest-rated hazards are Cold Wave (Medium, $9M EAL), Hail (Medium, $2M EAL), Lightning (Medium, $867K EAL). These account for most of the county's expected annual losses.
How does Portage County compare to other Wisconsin counties?
Portage County ranks #37 of 72 Wisconsin counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Portage County had?
FEMA records 12 federal disaster declarations for Portage County since 1973, most often 4 for severe storm events and 3 for flood events. The most recent was Covid-19 Pandemic, declared in April 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. Portage County's $36M EAL is a statistical average, not a guarantee for any specific year or address.