Foxe Basin is a shallow basin with strong tides that is seasonally ice covered by a notoriously thick and dirty seasonal ice pack. Despite its unusual dirty appearance, its role in the formation of deep water and the risk it presents along a proposed year-round shipping route, this ice pack remains relatively unstudied. Here, we use modern spaceborne observations and results from a high-resolution ice-ocean model to characterize the ice pack and examine the processes that lead to its extreme thickness and unique discoloration. We first identify a persistent polynya in southeastern Foxe Basin that is a key site for ice production. Using a newly developed approach to process ICESat-2 altimetry data we provide improved observations of total (snow+ice) freeboards, which reach up to 60 cm in central and eastern Foxe Basin. Using coastal observations of snow depth, we estimate an ice freeboard of 35 cm, which corresponds to an ice thickness of around 3m. This is quite thick for a seasonal ice cover at this latitude, highlighting the role of tidal dynamics in thickening the ice in Foxe Basin. Tides also lead to dirty appearance of the ice as they resuspend sediment from the shallow seafloor and lead to new ice growth within the heavily fractured ice pack. Overall, we provide the first in-depth view of the formation, growth and melt of a thick, dirty ice pack in Foxe Basin and comment on its role in both deep water formation and risk posed to potential shipping operations in the area.