Fishing the Fall Turnover
If you fish lakes with well-defined summer thermoclines, chances are, fall turnover is on the horizon. September through November is prime turnover time in the Southeast and Midwest.
The catalyst for turnover happens when surface water temperatures drop lower than the lake-bottom water temperature – usually into the low 70s to middle 60s. That cooling water becomes denser and begins to “sink” to the bottom, displacing the deepest water and forcing it to rise to the top. Essentially, the top and bottom layers, which stratified during the heat of summer, flip-flop. So, in a sense, a bass’ world is literally turned upside down.
Signs of Fall Turnover
Usually, even the mildest of turnovers are detectable by sight. The telltale sign is that the water color looks off. It’s usually darker, not muddy from run-off, but colored more like tea from the tannins trapped on the bottom all summer.
Intense turnovers are very obvious, with noticeably dark water and rotting organic matter, debris, bubbles, and even an unpleasant odor all wafting up from the bottom. Turnover doesn’t happen all at one time, either. Different parts of the lake turn over at different times, with deeper basins being the last to flip.
The Turnover Trap and How to Avoid It
The few times I’ve covered tournaments where true fall turnovers were occurring, I noticed pros had a common opinion about the turnover: avoid it! With so much change going on during a tumultuous turnover phase, the bass don’t seem to have much appetite.
The good news is, much like outrunning a stagnant tide on a tidal fishery, you can usually avoid the turnover, even as it’s happening.
Hunt for Remaining Thermoclines
One strategy is to fish places where the water has not turned over yet, and the thermocline is still in place. Thermoclines are detectable on a sonar unit, and bass will be positioned just above the thermocline.
Seek Out Current
Another tactic is to run away from the turbid turnover areas and search for current. Current keeps thermoclines and turnovers at bay. That’s why large power production reservoirs don’t usually develop hard, stubborn thermoclines that cause turnovers. The Deep Dive app is a strong asset when looking for current. The Stream Flow function will show all the areas where current enters a lake. Try venturing far back into creeks or going up the primary river arms to find flow.
Keep It Shallow
Another way to avoid turnover is to fish up shallow. Turnover is usually a main-lake phenomenon. Putting a “barrier” between you and the main lake is a good way to avoid the gunky water produced by turnover. Try hiding behind large flats in bays or fishing the backs of pockets with hard bends in them.
Play the Wind Wisely
Wind is your friend in the fall. But be wary of wind that’s pushing turnover plumes into the areas you’re fishing. Once the lake burps up its bottom water, wind will blow that water into banks and points; avoid those areas for a few days.
On the whole, turnovers last a week or so. If a hard cold front blows in, plummets the water temperature, and leaves severe north winds churning the surface, turnover might only take a few days. If a couple of mild fronts get the turnover going and the cool down is slow, then it might last as many as 7 or 8 days.
The Lake-Wide Reset
Once turnover is complete and the water has mixed, the lake becomes more homogeneous in terms of water temperature and oxygen. Water temperatures will range from 65 to 55 degrees throughout the lake. This allows bass and baitfish to use the whole water column again.
With the lake-wide reset of a fall turnover, bass inherently know it’s time to put the feedbag on before winter really craters the water temperatures. So, if you see the signs of fall turnover occurring on your lake, know that the best part of the fall transition is about to happen.
