Ice storms are a major source of tree mortality in some regions of the eastern North American deciduous forest, but are rare in the boreal forest. As climate changes, ice storms are predicted to be more common in the boreal forest, creating new challenges for forest management. In 2012, an ice storm damaged Pinus banksiana (Lamb.) stands throughout southeast Manitoba, Canada. We assessed damage in a 98- and a 32-yr-old stand. In both stands, half the trees broke near the base of the crown. Trees with a deeper crown were more likely to break in the young stand and less likely to break in the old stand. In the young stand taller trees were also more likely to break. There was no relationship between tree diameter and the probability of a tree breaking in either stand. Tree mortality increased the bare area around surviving trees by 52% and 119% in the young and old stands, respectively. This resulted in a 42% increase in canopy openness in the old stand but did not alter the pattern of spatial distribution of trees. Before the storm, trees in the young stand showed a dispersed distribution, indicative of density-dependent mortality. This dispersion was lost after the storm and suggests that, along with selection of shorter trees, ice storms reorganize the structure of forests undergoing self-thinning.