East Coast Lows (ECLs) are responsible for a large proportion of high impact weather on Australia's east coast, including heavy rain and flooding, strong winds, large waves and coastal erosion. The most severe and impactful events typically have a complex vertical structure, with a strong upper trough or cut off low as well as intense surface cyclogenesis. While the vertical structure of ECLs is playing an increasing role in weather forecasting, climate studies typically focus on low pressure systems which are objectively identified from a single level, such as mean sea level pressure or 500 hPa geopotential height. In this study, we track cyclones over 6 atmospheric levels between the surface and 500 hPa, to distinguish systems with a deep vertical structure from shallow surface-only or upper-only systems. This allows us to quantify the importance of cyclone depth to the intensity of the ECL, its temporal development, and its likelihood of producing significant impacts including strong winds, heavy rainfall, and lightning.