Trying to get light into the paradigm of forecasting geomagnetic activity, we have looked for a relationship between geoeffectiveness and the orientation and helicity of magnetic clouds. During the years 1995–2000, we have selected all the geomagnetic storms with Dst index less than −70 nT. Then, we have inspected WIND data looking for a possible magnetic cloud related to every storm event. When a magnetic cloud is encountered, we have fitted to experimental data a model that we have developed for the magnetic cloud topology in order to obtain the attitude of the magnetic cloud and its helicity. On the basis of the results obtained, a close relationship is observed between the orientation of the magnetic cloud and its helicity, and the geomagnetic activity. © 2003 American Institute of Physics