EVANSTON, Ill. — Four staff members at Northwestern University were injured after a tree fell onto a sidewalk in Evanston, according to police.

The incident happened after noon Thursday in the 2000 block of Sheridan, near Jacobs Center on Northwestern University’s Evanston campus.

According to police, a tree fell striking four pedestrians. Three were transported to Evanston Hospital, one in critical condition and two in serious condition. One person was released at the scene.

University leaders said all four people who were injured were staff members.

“It was just shocking,” Ashna Patel, a student, said. “I guess it’s just kind of scary especially when you’re walking to class.”

Evanston fire officials said the weather was likely a factor of the incident.

“The snow, ice, wind combination contributed most likely to the falling of a fairly large tree that resulted in injuries to the victims here today,” Evanston Fire Department Division Chief Matt Smith said.

University leaders said they are working to find out what exactly caused the tree to fall.

“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,” university spokesperson Eliza Larson said. “Crews also have been called in to assess and fix damage to nearby power lines.”

Students who frequently walk to class in this area were shaken by what happened.

“We don’t go through that path specifically but Sheridan really is an area that all of us walk through all the time,” Julia Sadernberg, a student, said. “So it is pretty shocking and kind of scary.”