September Fishing on the Yakima River and "Flip Flop" Defined

September 3, 2017

The River Flip Flop 

Check out the graph below, this is an annual look at the Yakima River's flow pattern: 

The term "flip flop" defines the river flow pattern from going very high during the summer, to low during the fall.  Right around Labor Day weekend each year the river flows are greatly reduced as the irrigation demand in the lower valley subsides and the reservoirs in the headwaters of the Yakima begin to run low.  At this time, the river flows on the Tieton River (a famous whitewater destination about 45 minutes south of our lodge) receives increased flows to compensate for the irrigation demand downstream.  This is flip flop.

September is also the time of year we begin to see all those old familiar faces that fish in the spring and fall when the river is wader friendly and easy for pontoon boats.  If you are a DIY angler from now through Thanksgiving is the best and most consistent time to wade fish or float in a personal watercraft boat.  It is also a GREAT time to rent a framed fishing raft from Red's.  The river flows are lower, its easier to row, and you'll be able to park the boat and wade fish.  

What does this mean for you?  Well, first off the river is low enough to hike around and wade fish.  This fall you can even cross the entire Yakima now in a few of the widest tailouts!  (be carefeul though and consider a wading staff.)  It also means much easier boating conditions for anglers.  The rowing, anchoring, and float timing is much easier now that the river is on its way down below 1,500 cfs by mid September.  By comparison, all through July we were operating at flows around 4000 cfs!  It is a big change.  I'm not sure exactly where the flow will be this year with the low water, but it will be a wade fisherman's dream.

Strategies and Suggestions:

If you are with a guide, just be sure to respect and appreciate the sensitivity that these trout have to the presentation.  Fishing big dry flies was hard enough when the flows were up, choppy, and a little noisy.  As they subside and the water gets calmer it will require cleaner casts and deliveries.  Concentrate on the drift and don't just hope a fish bites your fly... use your fly to hunt them down where they live.

If you are in your own boat, think about shortening up your floats and working the water in more detail. You won't be able to just "power float" downstream chucking hoppers at the bank anymore.  Delicate drifts will be required and you need to disect the seamlines.

If you are wading, THIS IS YOUR TIME!!!!!!!  Get in the river, look for whitewater and fast riffles mid-river, especially with small nymphs.  Also, look for spots that you can get out mid river and cast small terrestrials like Tupac Stoneflies hint hint back towards the shore.  The fish will be in as little as 8" of water under the grass banks as long as its moving. This is the BEST time to wade fish the Yakima.  

The fish also adjust their holding spots and feeding patterns.  The fish are essentially forced to move off the banks into mid-river boulder gardens, ledges, and pools.  On the hot days try the fastest riffles.  For the angler on foot this makes them much more accessible.  After the first few frosty nights the fish will move into more defined pools.  Look for walking speed water where you cannot identify the bottom during this time.