A synoptic monitoring program of Mars using the Wide Field Planetary Camera 2 on board the Hubble Space Telescope has resulted in the observation of discrete dust activity for two dates following the 1995 opposition. Data obtained on April 8 (LS=82¿) and August 21, 1995 (LS=145¿) reveal the presence of local dust storms in the northern polar region. In addition, the August images show activity over the Hellas basin. We present a multispectral analysis of the data from which we derive lower bounds to the atmospheric dust loading. Our technique directly models the absolute photometry, and consequently also provides estimates of the cloud opacity and the ozone columns for the regions analyzed.¿ 1997 American Geophysical Union