Competitive big mountain freeskiers pushed the limits Friday at the Subaru Squaw Valley USA Freeskiing Open while crowds of sun-drenched spectators indulged in the top-shelf performance. Athletes took turns negotiating The Headwall’s ominous vertical playground of wind-buffed stashes, cliffs, and chimney-wide chutes for what became a tit-for-tat showdown that lasted through the entire day’s final rounds.