"We've never seen anything like this before," said Hamilton County Sheriff Jim Neil at a Tuesday press conference.
Authorities shut down both directions of I-275 around 11:30 a.m when a snow burst of white-out conditions caused the massive pile-up in the westbound direction at the 35.8 mile marker between the Colerain Avenue exit and Hamilton Avenue exit.
Eastbound I-275 reopened around 5 p.m. and westbound I-275 reopened around 6:30 p.m.
Reagan was struck by a cable median barrier after she exited a damaged vehicle and was standing in the median, according to police. She was transported to Mercy Fairfield Hospital where she was pronounced dead. The Butler County coroner's office determined cause of death to be an accidental head injury.
Authorities said two other children, ages 4 and 5, were transported to local hospitals.
Officials also said at least four of those injured in the crash were initially listed in critical condition.
The first crews on the scene used the jaws of life to free four people from three separate cars, Colerain Township Fire Captain Darrain Edwards said.
Several passenger vehicles were trapped underneath multiple semi trucks when paramedics arrived at the scene, according to officials.
Officials also said that a steel cable that ended up in the middle of the roadway that is usually used to stop cars from crossing the median made a bad situation worse after the initial few collisions.
25 police officers and firefighters from 12 different departments responded to the scene and there were at least 20 transports to local hospitals, but none have life-threatening injuries, officials said.
"I am so proud of the men and women in uniform in Hamilton County," Neil said. "For the magnitude of the crash... [the response] went well."
Authorities say the major gust of snow took visibility down to zero on the interstate, which caused the massive accident.
Numerous vehicles were towed from the scene by Hamilton County sheriff's wreckers. The owners of those vehicles will be contacted by the Sheriff's Traffic Safety Unit and advised of their vehicle's location. Several Metro buses were called to the scene to transport those whose vehicles were inoperable at the scene of the chain-reaction crash.
Neil said the accident reconstruction will take a while, but they will have documentation for drivers to make insurance claims on their involvement in the crash.
Stay with 9 On Your Side and WCPO.com for updates as they become available.