As we go into the fall months, we are in a time period where we will face fall turnovers in the pond waters. Turnovers occur naturally in the fall. The incremental drop in air temperature slowly decreases the surface water temperature, and the layers in the pond mix gradually. This gradual mixing rarely causes a fish kill. On the other hand, rapid turnover can cause a fish kill by quickly diluting the oxygen in the pond. Rapid turnovers can occur anytime during the warmer months of the year when ponds are stratified, and they most often coincide with storm events or windy days. A cold rain or the blowing winds of a storm front can cause rapid mixing and result in a fish kill.