An interesting feature of previous sea ice modeling studies et al., 1976> was the multiyear cycles in sea ice thickness despite repeating year to year forcing. It is shown here that a number of factors combine to produce these cycles. The most important of these is the insulating properties of the snow layer; however, the timing of the refreezing of new ice at the end of an ice free summer season, and the vertical ocean flux play a role in determining the length and character of these cycles. It is also shown that the inclusion of the formation of white ice in the model greatly reduces its ability to produce multiyear cycles.