We used the database of Fairfield et al. [1994>, which includes several tens of thousands three-component magnetic measurements, to study the external magnetic field at distances of 10 RE>x>-30 RE under three levels of storm activity: Dst>0, -50 and Dst<-50 nT. The field pattern is obtained for a number of magnetospheric planes. In the major part of the equatorial plane a depression of the magnetic field takes place, expanding and growing with the increase of storm activity. For the midnight sector the point of the deepest depression is located at the distance of a few Earth radii. In the magnetotail lobes the Bx field component also grows with storm activity, the most pronounced growth being displayed in the near-Earth lobe regions. The external field in the noon-midnight meridian plane resembles the field produced by the cross-tail current, intensifying with the enhancement of the storm time depression. ¿ 2000 American Geophysical Union