Wind-driven mixing and Ekman pumping from slow-moving tropical cyclones (TCs) can bring nutrients to the euphotic zone, promoting phytoplankton blooms (TC-PBs) observable by satellite remote sensing. We examine an exceptional (z-score = 18-48) TC-PB induced by category-1 Cyclone Oma near the South Pacific island of Vanuatu in February 2019, the most extreme event in the observed satellite record of South Pacific surface Chlorophyll-a (Chl-a). Examining 15 South Pacific TC-PBs since 1997, we identify a “hover” parameter derivable from storm track data correlated with post-TC surface Chl-a (r=0.83). Using a dataset of synthetic storm tracks, we show revisit times for South Pacific TC-PBs are O(250) years, and O(1,500) years for Oma-scale TC-PBs. The episodic, extreme, but consistent nature of such events means they may imprint on sediment records. If so, we show their signature could be used to reconstruct past TC variability.