Observations made in the 1994 Antarctic vortex show that Cly recovered completely into HCl following conversion of Cly reservoir species to active radicals, and NOx constituted a 4--5 times higher fraction of NOy inside the vortex than outside. Measurements made in October and November from the Airborne Southern Hemisphere Ozone Expedition/Measurements of the Atmospheric Effects of Stratospheric Aircraft (ASHOE/MAESA) ER-2 aircraft mission, the third Atmospheric Laboratory for Applications and Science (ATLAS-3) space shuttle mission, and the Upper Atmosphere Research Satellite (UARS) demonstrate that this unusual partitioning of Cly and NOy was maintained for at least 4 weeks in the springtime vortex. In response to severe ozone loss, abundances of HCl and NOx remained high despite temperatures low enough to reactivate Cly and convert NOx to HNO3 via heterogeneous processes. Thus, under severely ozone depleted conditions, high HCl and NOx abundances in the vortex are maintained until the vortex breaks up or an influx of ozone-rich extravortex air is entrained into the vortex. These observations suggest that the flux of extravortex air entering the core of the lower stratospheric vortex was small or negligible above ~400 K during late spring, despite weakening of the vortex during this time period. Results of a photochemical model constrained by the measurements suggest that extravortex air entrained into the vortex during October and early November made up less than 5% of the vortex core air at 409 K. The model results also show that heterogeneous chemistry has little effect on the Cly and NOy partitioning once high abundances of HCl have been attained under ozone depleted conditions, even when aerosol loading is high. ¿ 1999 American Geophysical Union