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Chicago survival atlas

Cook County, Illinois

Reviewed · Data: FEMA National Risk Index v1.20 (December 2025) · U.S. Census Bureau Vintage 2025 · By SOS.city, made by the people for the people
In an emergency, call 911

Chicago’s biggest natural hazards are inland flooding, cold waves and tornadoes. In FEMA’s National Risk Index they make up 88% of the natural-hazard risk for Cook County, home to all of Chicago’s 2.7 million residents. FEMA rates the county’s overall risk Very High. Here is what to do for each, step by step.

People
2,731,585
Census estimate, July 1, 2025. No. 3 in the U.S.
County
Cook County
All of Chicago’s residents. FEMA rates counties, not cities.
Overall risk
Very High
Score 99.96 of 100. No. 2 of the 10 largest U.S. cities.
Expected loss
$2.4 billion
A year, from all 18 natural hazards (FEMA estimate).
Top 3 hazards
88%
of the county’s risk comes from these three: Inland flooding · Cold wave · Tornado.

What to do for Chicago’s top hazards

The one rule to remember, then the first steps, word for word from our guides. Each guide lists its sources.

No. 1 · 45% of the risk · Very High

Inland flooding

FEMA score 99.93: higher than 99.9% of U.S. counties. Expected loss $1.1 billion a year.

RememberTurn around, don't drown.
  1. Get to high ground now.
  2. Never walk, swim or drive into floodwater. 6 inches of moving water can knock you down; 12 inches carries away most cars.
  3. Car stalls in rising water: get out to higher ground if you safely can. Trapped in fast water: stay inside; if water rises inside, get on the roof.
Every step: What to do in a flood or flash flood
Source // National Weather Service: Turn Around Don’t Drown · Ready.gov: Floods
No. 2 · 29% of the risk · Very High

Cold wave

FEMA score 100.00: the highest of any U.S. county. Expected loss $700 million a year.

RememberOne warm room. Never heat with an oven or a grill.
  1. One warm room at home. Never heat with an oven or a grill.
  2. Signs: shivering, confusion, fumbling hands, slurred speech, drowsiness.
  3. Get them somewhere warm. Take off wet clothing.
Every step: What to do in a winter storm or blizzard
Source // National Weather Service: Winter safety · National Weather Service: During a winter storm
No. 3 · 14% of the risk · Very High

Tornado

FEMA score 99.96: higher than 99.9% of U.S. counties. Expected loss $345 million a year.

RememberLowest floor, interior room, cover your head.
  1. Go to the lowest floor: a small interior room away from windows.
  2. Cover your head and neck.
  3. In a mobile home or a car: get to a sturdy building.
Every step: What to do in a tornado warning
Source // National Weather Service: During a tornado · National Weather Service: Tornado safety
Emergency911
Poison Help1-800-222-1222
Can’t reach family?Text, don’t call. Texts often get through when calls don’t.

All 18 natural hazards in Chicago, ranked

Ranked by each hazard’s share of Cook County’s risk in FEMA’s National Risk Index. The score compares the county with every other U.S. county for that one hazard.

#HazardShare of riskFEMA ratingScoreExpected loss a yearThe rule
1 Inland flooding 45% Very High 99.93 $1.1 billion Turn around, don't drown.
2 Cold wave 29% Very High 100.00 $700 million One warm room. Never heat with an oven or a grill.
3 Tornado 14% Very High 99.96 $345 million Lowest floor, interior room, cover your head.
4 Heat wave 8.0% Very High 99.83 $193 million Get somewhere cool. Check on anyone who lives alone.
5 Earthquake 2.4% Relatively High 98.40 $57.3 million Drop. Cover. Hold on.
6 Strong wind 0.5% Very High 99.55 $11.6 million Shelter in an interior room, away from windows.
7 Hail 0.5% Relatively High 99.14 $11.1 million Get indoors, away from windows.
8 Winter weather 0.2% Very High 100.00 $4.4 million Stay in your shelter, or stay with your car.
9 Lightning 0.1% Very High 98.15 $2.7 million When thunder roars, go indoors.
10 Ice storm <0.1% Very High 97.16 $2.0 million Stay off the roads. One warm room.
11 Hurricane <0.1% Very Low 48.89 $57,000 Know your evacuation zone. Told to go? Go early.
12 Wildfire <0.1% Very Low 55.78 $56,000 Leave early. Know two ways out.
13 Coastal flooding <0.1% Relatively Low 44.00 $37,000 Run from the water. Hide from the wind.
14 Drought <0.1% Very Low 25.73 $12,000 Store water now: 1 gallon per person per day.
15 Landslide <0.1% Very Low 56.36 $2,000 Follow local alerts. Leave when officials say so.
– Avalanche – Not applicable – – Check your local avalanche center before backcountry travel.
– Tsunami – Insufficient data – – Strong or long shaking near the sea: go high now.
– Volcanic activity – Not applicable – – Evacuate early. In ashfall, stay in and wear an N95.

Source // FEMA National Risk Index v1.20 (December 2025), county 17031. Rules: SOS.city survival guides.

How to read these numbers

  • Share of risk. For each hazard, FEMA estimates the loss each year to buildings, people and farms, then adjusts it for social vulnerability and community resilience. The county’s overall risk is the sum of all 18, so the share shows how much of it each hazard carries.
  • Score. A percentile from 0 to 100. A score of 99.5 means the county’s risk for that hazard is higher than 99.5% of U.S. counties.
  • Rating. FEMA sorts counties into five groups, from Very Low to Very High.
  • Big places rank high. Expected losses grow with the number of people and buildings exposed, so large urban counties rank high on many hazards. A high rating means plan for it, not that it will happen this year.
  • County, not street. These ratings cover the whole county. For flood risk at your address, look it up on the FEMA Flood Map Service Center.
  • Cook County is rated Relatively High for social vulnerability and Relatively High for community resilience. Both feed into its overall rating.

Questions people ask

What natural disasters is Chicago most at risk for?

Chicago’s biggest natural hazards are inland flooding, cold waves and tornadoes. In FEMA’s National Risk Index they make up 88% of the natural-hazard risk for Cook County, home to all of Chicago’s 2.7 million residents. FEMA rates the county’s overall risk Very High.

How does FEMA rate Chicago’s overall disaster risk?

FEMA’s National Risk Index rates the overall risk of Cook County Very High, with a score of 99.96 out of 100. The score is a percentile: Cook County’s overall risk is higher than 99.9% of U.S. counties. Expected losses from natural hazards there average $2.4 billion a year.

What should I do first to get ready in Chicago?

Write down your top three: inland flooding, cold waves and tornadoes. Turn on Emergency Alerts on every phone and sign up for your county’s alerts. Store water: 1 gallon per person per day for at least 3 days, 2 weeks if you can.

Sources

Every number on this page comes from these public datasets. We check them when we review the page.

General safety information, not medical advice. In an emergency, call 911 and follow local officials.

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