Calamity
mediumSevere weatherCalamity Score: 34

Severe Weather in United States

MarionUnited StatesNOAA

This alert expired on 19 May 2026 at 02:00 UTC. It is kept here as a record.

It is the 6th strongest of the 63 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 10 more were recorded here in the fortnight before it.

What the source measured

NOAA reported: Flash Flood Warning issued May 18 at 2:54PM CDT until May 18 at 9:00PM CDT by NWS St Louis MO

An estimated 15,087 people live within 50 km of this point.

Nearby, since 15 March 2026

How we know

Confirmed by 23 independent sources, including NOAA.

Our own score for this event is 34 out of 100, at 89 % confidence.

The score is ours, computed from intensity, exposed population and local history — not the source’s.

Event Data

TypeSevere weather
Severitymedium
Calamity Score (ours)34 / 100
Our confidence89%
Coordinates38.7210, -88.8885
Nearest CityMount Vernon (45 km)
Population Exposed15.1K within 50 km
Impact Tiersignificant
Timestamp2026-05-18T19:54:00.000Z
Sourcehttps://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.0fc10db8c81f7b7f61965864aea49e59

Score Breakdown

35
intensity
40
population
0
cascading
80
historical

Technical Details

EventFlash Flood Warning
UrgencyImmediate
CertaintyLikely
AreaDescBond, IL; Clinton, IL; Fayette, IL; Madison, IL; Marion, IL; St. Clair, IL; Washington, IL; Clay, IL; Clinton, IL; Fayette, IL; Marion, IL and 1 more areas
HeadlineFlash Flood Warning issued May 18 at 2:54PM CDT until May 18 at 9:00PM CDT by NWS St Louis MO
Expires2026-05-18T21:00:00-05:00
SenderNameNWS St Louis MO
HasExactCoordstrue
MergedCount4
MergedIds["noaa_urn:oid:2.49.0.1.840.0.0fc10db8c81f7b7f61965864aea49e59a5f36434.001.1","noaa_urn:oid:2.49.0.1.840.0.913a8a86c94d4e638a15dcce4e3219a27fb4b386.001.1","noaa_urn:oid:2.49.0.1.840.0.981763280e670dafdad02306926ecdd4a788a568.001.1","noaa_urn:oid:2.49.0.1.840.0.acb5c63cf3a4cdea24b1f0e617f2449d79c4996e.001.1"]
Iem TypeSummaryR
Iem Magnitude2.3
Iem UnitInch
Iem CityEffingham County Airpor
Iem CountyEffingham
Iem StateIL
Iem WfoILX
Iem RemarkAWOS station K1H2 Effingham Arpt.
MergedSources[{"id":"iem_E_39.060_-88.750_1779128580000","source":"iem","severity":"low","severityValue":25,"timestamp":1779128580000,"latitude":39.06,"longitude":-88.75},{"id":"iem_R_39.070_-88.530_1779129300000","source":"iem","severity":"low","severityValue":25,"timestamp":1779129300000,"latitude":39.07,"longitude":-88.53},{"id":"iem_R_39.020_-88.570_1779126300000","source":"iem","severity":"low","severityValue":25,"timestamp":1779126300000,"latitude":39.02,"longitude":-88.57},{"id":"iem_R_38.980_-88.170_1779129000000","source":"iem","severity":"low","severityValue":25,"timestamp":1779129000000,"latitude":38.98,"longitude":-88.17},{"id":"iem_R_38.980_-88.170_1779128100000","source":"iem","severity":"low","severityValue":25,"timestamp":1779128100000,"latitude":38.98,"longitude":-88.17},{"id":"iem_R_39.070_-88.530_1779123300000","source":"iem","severity":"low","severityValue":25,"timestamp":1779123300000,"latitude":39.07,"longitude":-88.53},{"id":"iem_R_39.150_-88.530_1779126300000","source":"iem","severity":"low","severityValue":25,"timestamp":1779126300000,"latitude":39.15,"longitude":-88.53},{"id":"iem_R_39.070_-88.530_1779125700000","source":"iem","severity":"low","severityValue":25,"timestamp":1779125700000,"latitude":39.07,"longitude":-88.53},{"id":"iem_E_39.170_-88.380_1779128580000","source":"iem","severity":"low","severityValue":25,"timestamp":1779128580000,"latitude":39.17,"longitude":-88.38},{"id":"iem_R_39.150_-88.530_1779129000000","source":"iem","severity":"low","severityValue":25,"timestamp":1779129000000,"latitude":39.15,"longitude":-88.53},{"id":"iem_R_39.020_-88.570_1779124500000","source":"iem","severity":"low","severityValue":25,"timestamp":1779124500000,"latitude":39.02,"longitude":-88.57},{"id":"iem_R_39.150_-88.530_1779127200000","source":"iem","severity":"low","severityValue":25,"timestamp":1779127200000,"latitude":39.15,"longitude":-88.53},{"id":"iem_R_39.020_-88.570_1779129360000","source":"iem","severity":"low","severityValue":25,"timestamp":1779129360000,"latitude":39.02,"longitude":-88.57},{"id":"iem_R_39.130_-88.480_1779123600000","source":"iem","severity":"low","severityValue":25,"timestamp":1779123600000,"latitude":39.13,"longitude":-88.48},{"id":"iem_R_39.150_-88.530_1779124500000","source":"iem","severity":"low","severityValue":25,"timestamp":1779124500000,"latitude":39.15,"longitude":-88.53},{"id":"iem_R_39.130_-88.480_1779129000000","source":"iem","severity":"low","severityValue":25,"timestamp":1779129000000,"latitude":39.13,"longitude":-88.48},{"id":"iem_R_39.130_-88.480_1779124500000","source":"iem","severity":"low","severityValue":25,"timestamp":1779124500000,"latitude":39.13,"longitude":-88.48},{"id":"iem_R_39.020_-88.570_1779123900000","source":"iem","severity":"low","severityValue":25,"timestamp":1779123900000,"latitude":39.02,"longitude":-88.57},{"id":"iem_R_39.130_-88.480_1779126300000","source":"iem","severity":"low","severityValue":25,"timestamp":1779126300000,"latitude":39.13,"longitude":-88.48},{"id":"iem_E_39.130_-88.470_1779129000000","source":"iem","severity":"low","severityValue":25,"timestamp":1779129000000,"latitude":39.13,"longitude":-88.47},{"id":"iem_R_38.980_-88.170_1779126300000","source":"iem","severity":"low","severityValue":25,"timestamp":1779126300000,"latitude":38.98,"longitude":-88.17},{"id":"iem_R_39.070_-88.530_1779126900000","source":"iem","severity":"low","severityValue":25,"timestamp":1779126900000,"latitude":39.07,"longitude":-88.53}]

Safety Information

During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.

Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.

This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.

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Calamity.live data shows a weather event with CalamityScore 34/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.