Episode narrative: Two rounds of strong to severe thunderstorms spawned 13 tornadoes across central Illinois during the afternoon and evening of March 31st...including an EF-3 tornado that killed 3 people in Robinson in Crawford County.  The first round of convection developed along a warm front lifting northeastward through the area during the afternoon.  These storms were primarily very large hail-producers, with up to baseball-sized (2.75 diameter) hail being reported in the town of Banner in Fulton County.  Once the warm front lifted into northern Illinois, a modestly unstable but highly sheared environment was in place during the late afternoon and evening...with CAPE values of 1500-2500J/kg and 0-6km bulk shear in excess of 70kt.  As a trailing cold front approached from the west, additional supercell thunderstorms developed that produced tornadoes, very large hail, and damaging wind gusts.  The cells eventually congealed into a broken line as they pushed eastward to the I-57 corridor by mid-evening.  Meanwhile, a discrete supercell ahead of the line tracked south of I-70, dropping the EF-3 tornado in Crawford County.

Tornado event in CRAWFORD County, ILLINOIS
Start: 31-MAR-23 20:03:00
End: 31-MAR-23 20:21:00
Direct deaths: 3
Property damage: 0.00K
Event narrative: This tornado crossed into western Crawford County from Jasper County at 9:03pm CDT.  The tornado tracked northeastward, doing minor structural damage to a machine shed along County Highway 1 near Pierceburg.  Numerous wooden power poles were snapped and heavy damage to trees was noted with tops sheared off about 30 feet above ground.  Structural damage to homes of the EF1-EF2 variety occurred as the tornado moved across County Highway 15 where two single family homes sustained major roof damage.  A mobile home was torn in half with its debris strewn about 20 yards in opposite directions.  Trees, while sparse in this area, were sheared about 20-30 feet above the ground.  Further east along County Highway 15, structural damage occurred to a large machine shed where a stationary semi-trailer blew into its west-facing wall causing the entire structure to fail.  The debris from the large machine shed then blew into an old, poorly anchored single-family residence and caused exterior walls to slide off its foundation.  Over the next 3 miles along the path of the tornado just before it reached the south side of Robinson, considerable tree damage was observed.

As the tornado tracked into the south side of Robinson, it narrowly missed a major oil refinery.  The tornado destroyed two manufactured homes resulting in two fatalities as it crossed County Highway 9 near the interchange of East 900th Avenue and North 1200th Street.  Damage to structures, trees, and wooden power poles was determined to be EF1-EF2.

Heavy structural damage (EF3) and an additional fatality were noted on the east side of Robinson near the interchange of State Highway 1 and East 1050th Avenue where a two-story masonry building experienced failure to its top story walls.  The adjacent properties also experienced heavy damage where the exterior walls of two  single-family homes collapsed.  Damage to trees and utility poles in this area was extensive due to the amount of debris strewn toward the northeast. 

The tornado then moved over Robinson Municipal Airport, destroying airport hangers and a small outbuilding.  The progressive collapse of the rigid frames of the metal building systems, which included steel beams measuring greater than 18 inches in diameter, caused the survey team to estimate EF3 damage at this point.

A continuous track of EF1 damage then extended northeastward across County Highway 5 where multiple single-family homes exhibited large sections of their roof structures removed.  In addition, multiple large machine sheds experienced a collapse of their wall structures. 

The survey team concluded that the storm likely maintained its intensity as it tracked northeastward toward the Wabash River, noting about a quarter-mile wide swath of heavy tree damage to distant tree lines as it continued toward the river.  The tornado then crossed the Wabash River into the National Weather Service Indianapolis County Warning Area (CWA) in western Sullivan County at 9:21pm CDT.