Instantaneous xy-positions of dark matter particles at the moment they reverse their orbital orientation, tracked over 10 Gyr in the nonrotating (NR) simulation. The left column shows reversals in the halo far from the disk (10 < z < 30 kpc) and the right column shows reversals in a slice of the dark matter halo containing the stellar bar (∣z∣ < 3 kpc). The top (bottom) two frames show particles that begin the simulation prograde (retrograde) and become retrograde (prograde). All frames were rotated to keep the stellar bar aligned with y = 0, denoted here by the dashed line. The bar rotates in a clockwise direction. We find that halo orbits near the plane of the bar are preferentially reversed with respect to the bar’s location.