by Bruce Middleton, April 09, 2007

Barometric changes change how we fish for bass…

Up here in the Pacific Northwest we live in one of the worlds most changeable weather areas in the United States. This is because of the Japanese current that circulates out in the Pacific Ocean, sometimes called the Pineapple Express. It has the distinct advantage of keeping the mean temperature quite stable most of the year, where we suffer far less severe winters and less hot summers than the rest of the nation. The problem with all this moderation is the fact that the weather is unstable and we receive tremendous amounts of rain each year. Now don’t get me wrong, I don’t mind not driving in chest high snow each year and I’m now at an age where 100 degree plus weather is far and away too hot to find me anywhere far from an air conditioner. But as for bass fishing, these constant rainstorms make for some of the most challenging fishing imaginable.

Up here we seldom have the luxury of several weeks of stable air and temperatures. In fact we’re lucky to get a couple days in a row of anything near stable. We western Washingtonians/Oregonians spend more time fishing during front conditions than all the other states put together. Now to be completely honest the summer months are our dry months but rain is not always a good indicator of barometric pressure. If you follow the still days verses the really windy days you will get a more accurate picture of events.

There are a lot of theories behind the fact that bass stop biting during and right after a cold/windy front moves by. Personally, you would think the little critters would be used to it by now and go about life just like the rest of us do, but of course, that is just not the way of things. The success rate falls off just the same as anywhere.

The most accepted theory is that bass are so sensitive to any change in water temperature and barometric change that the slightest change of any kind causes them to stop feeding until they adjust to those new conditions. When a cold front up here moves in and the air temperature changes from say, 78 degrees to 50 degrees, this has dramatic effect on the lake waters in the area. It can actually drop a shallow lakes temperature by up to 5 degrees or more depending on how long the front lasts. Now that is massive change in a matter of a day or two and the bass react to this almost immediately. Conversely, when the sun does come out, you can actually see bass in shallow rocky flats that warm up first. As the water rewarms the bass’s appetite returns and the bite returns to normal.

Many also believe that bass sense barometric pressure, the rise and fall of air pressure as heavy wet air moves in verses light hot air. For myself, I have a tough time with this particular theory for the simple fact that bass are aquatic. They live in water and not in the air. It would be like us being sensitive to changes in the troposphere above us. To me it is a stretch, not out of the realm of possibility, but a stretch.

This is going to generate a lot of angry email but I’ll go ahead say this anyway; Now I have written and read many articles on bass fishing and I have come up with a small theory of my own based on a few facts I have observed. While fishing the Columbia River once during a cold front the bass bite fell off. Now there is just no way that a few degree change in the air temperature could possible have made even the slightest change in the water temperature of a river that size. And since I don’t subscribe fully to the barometric pressure theory, what was left? Then it dawned on me, and the answer was so easy, the sun. I think the bass are more sensitive to the amount of light in the water than we think they are. Now don’t get ahead of me.

On sunny days, clear water dingy water, whatever, there is a curtain amount of peak light that reaches different levels of any given lake. On partly cloudy days, that light is lessened by say 20%, I’m guessing at this point because I’ve never done the proper research, and on a dark cloudy day the light levels are reduced by another 20%. Now take a rainy day. They are even darker than a normal cloudy day because of all the darker clouds and the extra water in the air. Say this farther reduces the ambient light by another 10%. You now have a full reduction of about ½ the normal light of a sunny day verses a rainy day. This should limit the bass’s range of sight by half.

Additionally, the rainfall introduced on the surface of the lake or river adds a tremendous amount of noise into that body of water. And since water conducts sound 6 times better than air, this would further hinder the bass’s ability to detect food by using his lateral lines and ears. So what does a bass do? Why he sinks to the bottom and waits for the front to pass by, the noise to cease and the light levels to return so he can again hunt efficiently.

Remember a bass will expend as little energy as possible to get a meal. I would think that this would naturally extend to waiting for a meal too. Baitfish are no different than bass too when it comes to cold fronts are far as I can see. They probably don’t care for falling temperatures in the water either. The lower light levels may reduce their ability to hide from the bass, since their natural camouflage depends on very specific light levels.

Now the sun comes out as the front passes by and the fishing is still poor at best, why? Well the bass are still down on the bottom and it takes some time for them to adjust to the light levels. Remember a bass doesn’t have eyelids and therefore buries itself in weeds and other shady areas to protect his eyes. That and the baitfish would be still camouflaged in full sunlight. So what you get is a at least a full day of bad fishing after the front passes by as all the fish readjust to light levels on a full day cycle. It’s just a theory but to me it makes more sense that a bass being sensitive to barometric pressure.

There just seems to me to be a whole host of aspects that contribute to a bite falling off during a cold front. Bass are creatures, like humans, who like a stable temperature to live in and that optimum temperature is 72 degrees just like us. But say you live down south where the water has risen to 80 or 85 degrees and the cold front lowers the temp by 5 degrees down to 75. Now in my mind this would more comfortable for the bass. But on the other hand the drop in temperature in just over, say 12 hours is a bit more of a shock than the bass care to tolerate all in one big drop. And vise versa, when the front is gone and the water pops back up to 80-85 again. That would be like walking out of an air-conditioned house into an oven. It would take some time to get used to, don’t you think?

There are two things I do know for sure about fishing for bass up here: 1- if your out on a lake and the weather changes and it starts to rain lightly, grab a spinner bait and start working any weed line you can find. 2- after any cold front has passed, find a shallow, hard bottomed, sunny lake bottom and use a Rapala original floating minnow in water 2 to 8 feet deep. These two tips will always bag you bass, they just never seem too fail.

It is always better fishing just before a front moves in as apposed to just after a front has gone by. The water temperature hasn’t dropped and the rain hasn’t started to beat the surface of the water making it harder for the bass to hear. So if you do go fishing during these unsettled times, go before it starts to rain or just as soon as it starts.

Now I know I have squat for scientific investigative proof here and that Department of Wildlife and University studies are a lot more advanced and sophisticated than my poor ideas but I do think that they hold merit. I’m just a fisherman who spends a lot of time out on the water trying to trick bass into biting an artificial lure under various weather conditions during the four seasons. But I do keep my eyes open and try really hard to learn the lessons the bass are trying to teach me whether I catch any or not. I have studied their habits and haunts, feeding patterns, movements and behaviors.

In the end, if I am proven wrong or right, it probably won’t change the way I fish for my favorite game fish the bass because the patterns I have developed over the years work just great for a amateur angler like me. Now if I ever turn pro, I may rethink what I believe and the lures and baits I use because there is a lot of southern fishing involved. That alone means different baitfish, different vegetation and a different climate to fish under. But for now, up here in western Washington/Oregon I’m doing just fine, thank you very much, and besides I fish most of the time for the shear fun of it and not to win prizes or money.

One of the most asked questions I get from readers is ‘where do I fish right after a cold front has gone through the area?’ In order to answer this question you first must understand what a cold front does to bass and how they react to it before during and after. Then you can begin to understand how and where to begin looking for theses bass during the different times of a front’s motion.

Before a front moves in, bass behave normally, that is to say they eat and metabolize food according to water temperature and food supplies in the water they inhabit. As a cold front moves in (according to more traditional theories) the barometric pressure interferes with their swim bladder making it harder for them to sustain neutral buoyancy and stay where they want to be. This all but forces them to sink to lower levels of the water and remain there until they can adjust and control their swim bladder with greater ease. After a cold front has passed though, they slowly become more and more active until they return to a normal active state for the water and food supply in the water they inhabit again.

Now this is a very simplified view of the bass’s world and the processes they go through as the weather changes. There are however, a great many other factors that must be taken into consideration like lower light levels, rain noise on the water surface, wind noise and current action in and on the water and a whole host of other factors that just seem to effect every aspect of a bass’s movements and life. But for our simplified version these will be all that we will be concerned with.

As a cold front moves in, bass will usually go into a quick and furious mini feeding frenzy. This is one reason I and other are so insistent that as soon as it starts to rain that you get out a good spinner bait and begin to work as much area of the lake as possible. A spinner bait is a great search lure and covers a lot of area in a short time. Combined with all the noise and flash it puts off it is a perfect lure to use when it starts to rain. Places to use it around include outside weed lines, points, and changes in bottom structure, around cover, around lily pads and reeds and around docks.

This is a run a and gun scenario where you are trying to cover as much of the lake as possible before the bass start to shut down and drop to the bottom. Because once they are done there, you are reduced to plastics.

Now after a cold front has passed though and the bass are beginning to recover and returning to a more normal condition, again you fish the same areas as just mentioned but this time with slow moving plastics. Plastics are the denizens of the deep bottom of the lake. They are worked slowly and deliberately and with great concentration. The real problem with time and bass fishing is that there is no really good search bait that covers a lot of area in a short time and still draws a lot of strikes. Yes you can use every type of search lure on the market, crank baits, spinners, lipless cranks, top waters and so but they just don’t give a true reading of what and where the bass are hold up and in how many numbers they are in.

The best compromise is to use a split-shot rig. This is a Carolina rig that is swam instead of left to lay on the bottom. By using a weightless rig or by using the lightest sinker possible you can cover a lot of area but it will take much longer than if you were using say a crank bait. Still it provides you with the look you want and at a cadence the bass prefer, slow and slower.

The real beauty of a split-shot rig is the total versatility it has when it comes to choosing the type, color, size and shape of the plastic you wish to try. The field of choice is unlimited. You can fish with a tube or a red craw or a Senko finesse worm. Creature baits, grubs, even items you use for trailers can be used as swim baits at this time with great success. And the depth of the water you fish in can be from 1 foot to 30 feet with no change in line, weight or lure. In fact fishing deeper is almost the preferred depth since most bass seem to go deep during a cold front.

This is also a great place to try a drop shot rig or just a straight jig and pig approach. But these slower methods are usually employed after a group of bass have been located on a depth finder. And speaking of which, I will say it again, a map of any lake you fish on regularly is worth its weight in gold. A good map of a lake’s bottom will show you all the likely places the bass will be during any given time of the year, after a cold front, or even where they will not be found. Where they will not be found is more important than where they will be found, as it will keep you from spending hours casting into empty water, and that is a waste of your time and effort. So if you can’t catch a bass after a cold front has moved pass, maybe it’s time to make a map of the lake so that you have a better picture of the lake the next you come back to fish it.

After a cold front has moved through the area, some of the best times to fish are in the afternoon to late afternoon. This is the time when any sunlight will have had a chance to warm up any shallow rocky or gravely areas of the lake. This will always draw bass to them because the water temperature is warmer. Bass are creatures of comfort and will move some distance if the water is more comfortable for them somewhere else. In these areas lures like an Original Floating Minnow by Rapala in silver size F11 is just the lure to use to catch these slightly faster moving bass.

So get out there and fish before the fronts hit and look for sunny shallow spots after the fronts have past. It’s the best way I know to take the pain in the bass out of front.

Bruce Middleton
bpmiddleton@peoplepc.com