( CNN ) -- A snowmobiler remains in critical condition after an accident at the X Games Aspen , his family said Monday . Caleb Moore , 25 , was competing in the snowmobile freestyle final Thursday in Aspen , Colorado , when he came up short while trying to do a back flip . The front skis of the machine clipped the landing hill and Moore shot forward over the handlebars . The 450-pound snowmobile struck him as he slid down the hill and the machine tumbled over him . `` 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 snowmobiler 's family said in a statement . St. Mary 's Hospital did n't immediately respond to CNN 's inquiry into Moore 's condition . The family statement said Moore was being `` closely monitored . '' Moore 's brother Colten also was involved in an accident during Thursday 's event . He was released from the hospital Saturday , according to his Facebook fan page . Colten Moore encouraged fans to pray for his brother . `` We continue to fight and pray for him , '' he wrote on Facebook . The X Games Aspen features competitors in snowmobiling , snowboard and skiing events . 2012 : X Games begin with a tribute to Sarah Burke .
NEW : Friend of injured rider encourages fan to pray for him . Caleb Johnson was competing in the snowmobile ##s event . He was trying to do a back flip with his machine when he came up short . He was hit by the machine while falling down the ski hill .