The snowboarder is grinding on a silver rail in the nighttime snow.
The snowboarder is out grinding in the dark.
grinding in the night time snow is rephrased as out grinding in the dark. night time is dark and in the snow implies outside.
exists e1 s1 x1 x2 x3 x4.(n_snow(x4) & a_nighttime(s1) & Theme(s1,x4) & n_snowboarder(x1) & on(e1,x2) & in(x2,x4) & n_rail(x2) & of(x2,x3) & n_silver(x3) & Actor(e1,x1) & v_grind(e1))
exists e1 s1 x1 x2.(n_dark(x2) & n_snowboarder(x1) & a_out(s1) & Manner(e1,s1) & in(e1,x2) & Actor(e1,x1) & v_grind(e1))