Per the SPC Database, 48 tornadoes occurred on March 20, 1976. Three were rated F4. In this summary, we will look at the first F4 of the day. It occurred during the early afternoon in Macon, Piatt, Champaign and Vermillion Counties in Illinois. The path length was 63.7 miles and the max width 800 yards. There were 18 reported injuries.
The 2nd F4 ripped through parts of Tippecanoe and Carroll Counties in IN including the town of West Lafayette. Here is an AMS Journal article about the event which shows photographic evidence of suction “debris” vortices: Link
The 3rd F4 moved through Oakland County, MI and the town of West Bloomfield. Here is an overview via the NWS Detroit: Link
This long-track Illinois tornado developed near Casner, 5 miles SE of Decatur. In this area, a house trailer was demolished and 5 homes sustained damage. The twister moved to the NE at approximately 50 mph. The Voorhies Clock Tower Barn, an area landmark was destroyed. Members of the Bement Fire Department followed the tornado to near Ivesdale. Storm Data noted that “the tornado was nearly a half-mile wide at the base and appeared to be filled with pieces of trees and buildings.” It grew to nearly a mile wide before approaching Sadorus.
It then narrowed to 1/2 mile wide again as it passed through town. Per Storm Data, “Multiple funnels were sighted at this point; an eyewitness described the tornado as two whirling clouds running side-by-side in the manner of an egg beater. Marks left in a field three miles southwest of Sadorus indicated that the tornado was composed of three or four suction spots (funnels) at that point.”
At Sadorus, 5 people were injured. 13 houses and 7 mobile homes were destroyed and 25 houses were damaged beyond repair. At least a dozen vehicles were crushed by falling debris.
The tornado continued to move to the northeast. Debris was found in fields and along parts of I-57 and US 45. Several homes were destroyed on the northern edge of Philo.
On IL 130 west of Sidney, a small van was caught up in the tornado and tossed into a field 1/2 mile away from where it was hit. The driver had serious injuries. A few miles to the NW of Sidney, several farm houses, outbuildings and cars were destroyed. Several farm buildings were destroyed south of St. Jospeh.
The tornado veered to the left and moved right through Ogden. Two funnels were visible at this point. A lumber yard, bank, water tower, grain elevator, fire house and several homes were destroyed. There were 5 injuries in town. The tornado lifted 5 miles NW of Danville.