  We show that the energy-weighted angular (zenith, azimuth) distribution of
extensive air showers (EAS), produced by Ultra High Energy (UHE) cosmic rays at
the Pierre Auger Observatory (PAO), has a thrust axis almost transverse to the
interplanetary magnetic field (IMF), with a thrust value $Tp \geq 0.64$ ( where
1.0 means a perfect alignment and 0.5 isotropy). This behavior strongly
suggests an effect of the IMF on the charged shower particles, producing
additional lateral scattering. We discuss the weakening of the Earth's magnetic
field during geomagnetic storms (30\% of observational time) when the IMF
becomes preponderant, strengthening the alignment.
