Tree falls on Northwestern University campus, injuring 4

A tree collapsed on Northwestern University's campus Thursday during a winter storm, injuring four people, one critically, authorities said.

Evanston police said the tree fell about noon and struck four pedestrians who were on a sidewalk at the campus just north of Chicago.

One person suffered serious injuries and was taken to Evanston Hospital with two others who had moderate injuries, said Matt Smith, a division chief with the Evanston Fire Department. He said the fourth person was treated at the scene.

One patient was in critical condition and two were in serious condition, the fire department later said in a news release.

The news release said a fourth patient was offered medical care and signed a patient refusal form.

University officials told people to avoid the area around the Jacobs Center as emergency crews responded.

"The university is working with an arborist to determine what caused the tree to fall, and if other trees in the area are potentially compromised," a statement from the university read. "Our thoughts are with the members of the community who were injured, as we await updates on their conditions."