According to a statement from Mont Tremblant Ski Resort, Richardson fell during a lesson on a beginners' trail.
"She did not show any visible sign of injury, but the ski patrol followed strict procedures and brought her back to the bottom of the slope and insisted she should see a doctor," the statement said.
Richardson, accompanied by her instructor, returned to her hotel, but about an hour after the fall was "not feeling good," the statement said. An ambulance was called, and Richardson was taken to a local hospital before being transferred to Hopital du Sacre-Coeur in Montreal. From there she was transferred to Lenox Hill Hospital in New York City.
Family, friends gather for viewing for Natasha Richardson Fri Mar 20, 11:21 PM By Mesfin Fekadu, The Associated Press
NEW YORK - Liam Neeson looked distraught but grateful for the outpouring of sympathy as he greeted grieving family members and friends who attended a private viewing for wife Natasha Richardson on Friday.
Neeson was the last to leave the viewing at the Upper East Side's American Irish Historical Society, where he was joined by the couple's sons, - Micheal, 13, and Daniel, 12 - as well as Richardson's mother, Vanessa Redgrave, and sister, Joely Richardson. An array of famous friends came to express their sadness about the family's sudden loss.
Neeson hugged friends as he left the society's building at 8:40 p.m., after more than six hours of receiving condolences from friends including Mike Nichols, Diane Sawyer, Matthew Modine, Ralph Fiennes, Uma Thurman, Ethan Hawke, and Sarah Jessica Parker.
Also among the stream of visitors were Kenneth Cole, Laura Linney, Fisher Stevens, Howard Stern, Stanley Tucci, Julianna Margulies and Mathilde Krim of the American Foundation of AIDS Research. Richardson had served on the charity's board of trustees since 2006.
"She looked incredibly beautiful," Krim said, adding that everyone appeared to be in shock and Neeson looked distraught as he received everybody.