During the polar vortex season, so-called streamers can transport tropical air towards the pole in the middle stratosphere. This tropical air can get trapped in high-pressure areas at high latitudes after the polar vortex breaks down. In this study, remote sensing instruments are used to observe the course of such streamers by measuring the scattered solar radiation. Aerosols get transported to high latitudes at an altitude of about 25–35 km, increasing the aerosol mass there significantly.