(CBS) — A tree branch fell on a babysitter who was watching three children at a park in the north side Rogers Park neighborhood.

Police, Fire Department and the Chicago Park District spokespersons say that the branch fell without warning on the woman during the noon hour Wednesday in Touhy Park, on the 1600 block of West Jarvis Avenue.

One of the woman’s legs was trapped beneath the tree branch. Police and fire personnel had to free the woman.

Chicago Fire Department spokesman Will Knight said that paramedics transported the woman in serious but stable condition to St. Francis Hospital, in Evanston.

The children were unhurt.

Chicago Park District spokesperson Jessica Maxey-Faulkner said the Park District had investigators on the scene attempting to determine what happened.

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