The present study investigates the ice production within a coastal polynya maintained by wind-driven offshore sea-ice transport. Most previous applications have assumed that ice divergence and dynamic open-water formation in such an area are mainly related to the effective export of frazil ice. This disregards the contributions of rapid thin-ice growth to the overall heat loss, ice production and salt releases, and neither takes into account the creation of open water due to ridging and rafting. Here a simple model is formulated that takes into account these processes. The model is applied to Storfjorden, a roughly 10 000 km² large polynya region within the Svalbard Archipelago. During recent years the latter has received much interest in terms of its ice and dense shelf-water production. Here it is shown that all three mentioned processes, frazil-ice dynamics, thin columnar-ice growth, and deformation, contribute significantly to the formation of open water and ice export from Storfjorden. The results further demonstrate that most previous estimates of integral ice formation and salt fluxes in the Storfjorden region are roughly a factor of 2 too low. The study also highlights the need for improved parameterizations of polynya dynamics and thermodynamics, as well as observations of deformation and frazil ice in such areas.