Finding the Hot Zone in the Run

fly fishing hot zone

The “hot zone” is an expression that refers to the exact spot or stretch in the run where trout will hit your nymph. It’s a common-enough phrase, but I began using it after a wade trip with a guide on the edge of Yellowstone National Park. If you locate the hot zone, you’ve discovered the Holy Grail.

We all know that fish have lies.

They hang in opportunistic or safe places in the river, such as prime lies, feeding lies, and/or sheltering lies. But on a more practical level, many runs, especially the deeper ones, seem to hold large pods of trout. Especially in the spring (rainbows) or fall (browns), fish stack up in some of the deeper pools. Some are spawning, others chase the spawners upriver and feed off the eggs.

Here are several quasi-truths of the so-called hot zone:

1. The hot zone is a narrow window.

Last fall, Steve (my podcast partner) and I fished a river with several deep runs. Near the end of the day, we walked back to a run that Steve had fished earlier in the day. I had not yet fished it. Steve started casting and immediately began catching fish.

It took me a good 15 minutes of casting, even with Steve’s instructions, to begin catching fish. Hitting the hot zone is easier to write about than to do in real time.

2. It’s easy to miss the hot zone entirely.

If you’re fishing a new stretch of river, it’s quite possible that you will miss the hot zone on any given run, especially if you’re moving too fast upriver.

Just a caveat: Too often new fly fishers will camp on one good run and cast for hours in the same place. I’m not advocating that. But if you’re fishing new waters, then patiently working the run is important to cover the possible lies of the fish.

Steve and I have a honey hole on the Lower Madison River that often gets passed by. It’s a ways up the trail into the back country from the access point. The more persistent fly fishers hike upriver, however, and often wade through our honey hole, but they never seem to linger. My guess is that they may catch one brown on the way through but have never had the kinds of afternoons that Steve and I have had.

3. Subtle takes can prevent you from identifying the hot zone.

This is the challenge of all nymph fishing, but reading what is a “take” and what is simply your nymph catching rocks or debris on the bottom of the river is not as easy as ordering black coffee at Starbucks: “I’ll have a grande Pike, please.”

The rule of thumb is to pay close attention to your indicator and then strike at every possible sign. What does it hurt if you strike and nothing is there? Nada. Just let your indicator continue to drift downstream. It’s better to react too often than to wait until you’re certain you have a real take.

4. Fly depth may be the biggest issue when searching for the hot zone.

Whether a smaller creek or bigger river, the depth of the runs change from run to run. So if you’re not adding split shot – or lengthening your indicator – you may not be deep enough.

The bigger issue, though, may be that you are not casting far enough upriver, giving your nymph time to bounce along the bottom in the hot zone. This is especially true in deeper pools. The right depth is key to the hot zone. While the typical solution is to add split shot to your rig, the better solution may be to cast farther upriver (if you can), so the nymph can sink to the perfect depth in the hot zone. The nymph should be at the right depth before it enters the hot zone.

5. After all your persistence and finesse, there may not be a hot zone.

Or there may be one, but the fish are not in the mood. So how do you really know?

If you’ve had one of those days where you’ve caught more than several fish from one run, then you obviously have hit the hot zone. You know it when you hit it. Keep searching!