An alpine or tundra slope where frost freeze and thaw cycles and wind create plant habitat in scree interstices. Freeze-thaw cycles push plants out of the soil, which is highly porous, so a fellfield is a difficult place for plants to grow. Fellfields often have a typical pattern: lines of rocks pushed out of the soil, and slid into a low region. Also known as "Fell Field".
I fell in the field but didn't get hurt because although I fell I didn't fall in a rocky fellfield.