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Chicago-area derecho, Jul 15–16, 2024

1 of 2 · The storm's data
forty°seventy

Chicago-area derecho, Jul 15–16, 2024

Chicago-area derecho, Jul 15–16, 2024

Chapter 4 · Into the night

Outages peak in Illinois.

Outages peak at 390,878 customers in Illinois, with Cook County the hardest hit. The line ends 562 mi from where it began.

04:15UTC · Tue, Jul 16, 2024 · 11:15 PM CDT Mon

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Replay of past events. For current weather and warnings, see weather.gov. Links are rule-based facts. About and credits

Replay · DE20240715

Chicago-area derecho: the story

Jul 15, 20:00 UTC – Jul 16, 07:00 UTC. Radar, severe thunderstorm and tornado warnings, storm reports and ground stops, in order, with 456 links that show their evidence.

  • 368 NWS warnings
  • 665 storm reports
  • 3 FAA airport programs
  • 1 derecho track (SPC)
  • 456 rule-based links
  • 390,878 customers out at the peak, in Illinois
  • 331 radar frames

Iowa

Jul 15

  1. The largest hail reported: 2.5 in at Vail, IA.Replay from here
  2. The derecho's line begins (Storm Prediction Center).Replay from here

Illinois

Jul 15–16

  1. NWS Quad Cities IA IL, IL issues the first Tornado Warning.Replay from here

Chicago

Jul 16

  1. The strongest measured gust: 105 mph at 3 S Camp Grove, IL.Replay from here

Into the night

Jul 16

  1. Peak outages: 390,878 customers out of power in Illinois. The most in one county: Cook County, IL, 155,204 out (7% of its customers) at 04:15 UTC.Replay from here
  2. The derecho's line ends, 562 mi from where it began.Replay from here

How we link records

RuleWhat it checksLinks
R4 solidA storm report inside a warning polygon while it was in effect445
R2 dashedAn airport program inside a warning that had been in effect for over 60 min (context)5
R1c solidA weather airport program inside a convective warning or watch, within 60 min of issuance4
R1o dashedThe same, for other hazards such as floods2

Solid lines mark rules that passed an independent check; dashed lines are context. Links are rule-based facts: each shows two records that overlap in place and time. How we know

Where this storm's data comes from

Every layer, the provider behind it and the period it covers.

LayerProviderPeriodRecords
MRMS SeamlessHSRNOAA/NSSL via Iowa Environmental MesonetJul 15, 20:00 UTC – Jul 16, 07:00 UTC331
NWS storm-based warning polygonsNOAA National Weather Service via Iowa Environmental MesonetJul 15, 20:00 UTC – Jul 16, 07:00 UTC368
NWS Local Storm ReportsNOAA National Weather Service via Iowa Environmental MesonetJul 15, 20:00 UTC – Jul 16, 07:00 UTC665
SPC derecho tableNOAA Storm Prediction CenterJul 15, 20:00 UTC – Jul 16, 07:00 UTC1
FAA airport programs (ground stops and ground delay programs)FAA Air Traffic Control System Command CenterJul 15, 20:00 UTC – Jul 16, 07:00 UTC3
ORNL EAGLE-IOak Ridge National LaboratoryJul 15, 20:00 UTC – Jul 16, 07:00 UTC503
  • Radar: NOAA/NSSL MRMS SeamlessHSR, via the Iowa Environmental Mesonet (IEM), Iowa State University
  • Warnings: NOAA/NWS, storm-based polygons via the Iowa Environmental Mesonet
  • Storm reports: NOAA/NWS Local Storm Reports via the Iowa Environmental Mesonet
  • Airport programs: FAA Air Traffic Control System Command Center
  • Derecho path: NOAA/NWS Storm Prediction Center derecho table (Squitieri et al. 2026)
  • Power outages: Oak Ridge National Laboratory, EAGLE-I (CC BY 4.0)
  • County boundaries: U.S. Census Bureau