The 17-year-old explained that she took a few selfies at the top of the jump and was in a rush, causing the phone to slip from her hand.
"I took a few selfies on top and then I was in a bit of a rush," Thomas told Sky Sport.
Mischa Thomas Loses Phone During Olympic Halfpipe Final
Olympic debutant Mischa Thomas finished eighth in the women's halfpipe but lost her phone during the second run after taking selfies.