Emergency responders rushed to the scene where they performed CPR before taking her to the hospital.
Speaking in a statement on their Instagram accounts, they said: "We are beyond devastated". The caption reads: "We are beyond devastated. Her love, her light, her spirit will never be forgotten", Mr Miller wrote. Our little princess girl loved life and lived it to its fullest everyday. In his Instagram post, Miller asked for privacy for his family.
The death of their daughter is under investigation, a representative of the Orange County sheriff's office said (via the AP).
Beck and Bode Miller has shared their grief after the tragedy.
Former Olympic gold medallist Bode Miller's daughter has died after a tragic accident.
Emeline Grier Cause of Death: How Did Bode Miller's Daughter Die?
We're told paramedics tried "advanced life support" but were unable to save her.
Skiing champion Bode Miller and his wife Morgan Miller.
The U.S. Ski and Snowboard team tweeted condolences to the Miller family. Miller also has two other children from previous relationships, a daughter named Neesyn and a son named Samuel. "#TeamUSA sends honest condolences to @MillerBode and his family, along with wishes of strength and comfort".
Volleyball star Morgan, who also shares a three-year old son, Nash, with her husband, is expecting the couple's third child, due in October this year.
Miller, 40, is the most decorated skier in U.S. history, with six medals in 2002, 2010 and 2014 Winter Games, including a gold in the super combined in Salt Lake City in 2002.