A low-frequency electric field is observed during crater formation by detonation of high explosive charges. The disturbance of the atmosphere's electric potential gradient at ground level was measured in the range of frequencies between 0 and 200 Hz. Our results indicate that explosions are capable of creating large electrical charge separations in the atmosphere. A simple model of field generation is proposed. Furthermore, a correlation between the magnitude of the explosion and the electric charge of the dust cloud is established. Using these results, estimates of the intensity of the electric field generated during meteorite impact crater formation is proposed. ¿ American Geophysical Union 1996