Hmmm. Looks interesting!
This is the Warrior Pose in Astanga yoga (allegedly).
According to Mandi who leads my group at Stoke Newington Yogahome, in Warrior pose the forward foot should be pointing forward. It is not in your picture.
The stretch in Warrior, as I understand it, comes because the torso is facing forward while the legs are facing sideways. I always find it a rather satisfactory position.
But you shouldn't do it on top of a Lakeland fell. No flat space beneath the feet. And where's the mat?