Field trials have been conducted at the Northern Plains Potato Growers Association Irrigated research site near Inkster, ND for approximately 10 years to evaluate yield and grade responses to single or double simulated hail events at various potato growth stages for various russet type potato cultivars. Seed pieces (2 oz) were planted on 36-inch rows and 12-inch spacing as soon as possible each year. Extension recommendations were used for cultural practices throughout the year. Single or double simulated hail events varied between 0% and 99% defoliation at one of four application timings: tuber initiation (TI), end of tuber initiation (ETI), early tuber bulking (ETB), and mid bulking (MB). Plots were harvested and graded into various categories. Environmental conditions immediately following simulated hail events influenced plant regrowth, especially with severe defoliation. Timing of the simulated hail event influenced yield. Yield reductions were primarily due to lower yield in the various grade categories. In general, all hail treatments lowered marketable and total yield compared to the nontreated. Even though regrowth was amazing, a second simulated hail event drastically reduced marketable yields.