Measurements by the Halogen Occultation Experiment (HALOE) during the austral spring of 1993 show anomalously high aerosol extinction profiles over the Weddell Sea on October 7 - October 9. With temperatures falling to 195 K and below, conditions were favourable for the formation of Polar Stratospheric Clouds (PSCs). Geopotential height fields from the United Kingdom Meteorological Office (UKMO) meteorological analyses suggest that the region of cold temperatures was being influenced by flow patterns in the mid troposphere. HALOE measurements of methane and water vapour mixing ratio, together with potential vorticity maps and wind field vectors from the UKMO analyses, suggest that there was transport of air across the pole from mid latitudes.