Snowmobiler Caleb Moore of Krum, Texas, remains in critical condition Tuesday after a crash last week during the Winter X Games in Aspen.

The 25-year-old was performing a flip Thursday when he caught the top of the hill that was serving as a landing area and went over the handlebars, landing face first into the snow. The snowmobile rolled over him, but he walked off with help and went to a hospital with a concussion.

Moore later developed bleeding around his heart and was flown to a hospital in Grand Junction for surgery Friday. The family said Sunday that Moore also had a complication involving his brain and they weren’t hopeful about his chances for survival.

“Caleb is in critical condition and is being closely monitored,” family spokeswoman Chelsea Lawson said Monday evening. “The Moores want to express their gratitude to all of Caleb’s fans, friends and family for their strong support and ask for continued prayers in the coming days. The family will not be making any other public statements for the time being. Thank you for respecting the family’s privacy during this difficult time.” The family declined further comment.

X Games officials said in a statement that their thoughts and prayers were with Caleb and his family.

“Still, when the world’s best compete at the highest level in any sport, risks remain. Caleb is a four-time X Games medalist who fell short on his rotation on a move he has landed several times previously,” the statement said.

They also said that they’ve paid close attention to safety issues during the event’s 18-year history.

Moore grew up racing all-terrain vehicles in Texas but later switched into snowmobiling. He began launching his snowmobile into pools of foam a month before the 2010 X Games. After a brief training run on snow ramps in Michigan, he joined the big leagues and never looked back.

If the Texan snowmobiler does not survive, it will mark the first fatality in the 17-year history of the Winter X Games.