Missouri River April May Fly Fishing Forecast

Missouri River Late April May Fly Fishing Forecast

Missouri River Late April May Fly Fishing Forecast

Snow on the ground. Green grasses below the white cover. Next week better air temps. And maybe less snow on the ground here locally.

This water update article along with fishing predictions is morphed with one from 2017. Interesting look along with the ’17 trout and water data included. Always important to see the past, and the data, to get a point of perspective of where we, the river, is currently at. Things do change. Fish populations, water conditions, aquatic vegetation states,

Missouri River Trout Populations

I will leave the numbers in red, that were current in 2017. Do we have more fishing pressure since 2017? Maybe. Does fishing pressure directly curtail the presence of trout, the increase, the successful growth and population increases? You tell us. It is currently 6 years beyond these numbers in red. 2023. Did we have desperate water levels in the past 6 years? You do the research. Look at USGS charts and make your own decision. But I will tell you it has not all been roses. Is the Missouri an incredible resource? Yes! Do may factors attribute to trout health? Certainly. What do you blame the trout number density increase on?

Rainbow populations are on the fall. rise 4816 6400 Rainbows/mile 10″ or better on the upper river. FWP shocks the Wolf Creek to Craig section and the Pelican Point to Cascade reach seasonally. Spring and fall, Three consecutive nights right, center, and left side. The same pools are sampled as to create some consistency.

500 1400 Rainbows/mile in the larger 20″ lengths keep us interested. A nice 4-5 year class is out there. Get some. We do not know the balance of the trout in the under 10″. That is a stat that is not available to us. But it has to be about the same number, at least. Probably more under 10″/mile than over.

Brown Trout seem to be dropping increasing and are now below above historic average levels. Some believe that they are on the increase. Simply not true. 1600 269/mile over 10 inches is the current data from Wolf Creek to Craig shocking surveys. The historical average is 563/mile. And about the same on the lower river as well. They are higher in percentage in the Cascade reach.

On the upper reach the rainbow outnumber the brown trout considerably. The brown trout on the upper reach have an age class of approximately 40 Browns/mile 20″-24″. And some of them eat a dry fly. Or a beefy streamer! This data from ’17. No new data that I have access to at this time. Forthcoming.

Summer Water Flow Projections

The Missouri River drainage area that we draw from is 13,000 square miles. Awesome huh. Last year as you remember we were in dire straits int he early spring. By now, late April ’22 we were beginning to see a cooler and wetter than normal weather pattern develop. The weather did actually change the outcome after, post-mid-April and the snow on the ground at that moment in time. A rare occurrence that nobody saw coming. Water managers, long time fishing guides, people actually from Montana, even Pete Cardinal did not see the spring that we had in 2022 coming. Cooler, wetter, longer spring than anybody could, would, predict. Water stayed, longer, cooler, wetter and we had a wonderful summer with historical water averages satisfied. One crazy year.

This year predicting about a 130% of average water year. That is the prediction so far. Again, update this week in regards to the latest plan, spoken about in the beginning or May.

Canyon Ferry is 70.7% full. Current inflows are about 5600cfs with outflows at 5900cfs. That is encouraging. We can see the movement of water out of Canyon Ferry in anticipation of the water coming from the hills and mountains in our drainage. The inflows will increase as the weather turns warmer and the snow can come off the hills into the Mo River basin.

I will speak with Stephanie Micek this week and get the late April update. Another b ig update as we move into the month of May.

Missouri River April May Fly Fishing Forecast

Water Year 2023

As you can see on the chart above we may have flows in the 7K 10K+ range for the month of June. Maximum probable flows about 10K 15K. For flows to exceed that we will have to have above average precipitation starting now.  Our flows will certainly be up above that of the past couple years as we do have the snow in the hills to provide a good summers worth of water. Bring it!

The wade dudes do not like the higher flows as they cannot wade fish as effectively. 6K is the flow that wade fishers like to keep their eyes on. 10K daily flows discourage the recreational boaters from launching. What will we see this spring?

Big high waters can happen with this start. If it begins to rain, and it can, we will have more water. Lots more water. It did in ’97. In ’98 too. Then not too many years ago in ’08-’11 we had higher than normal flows with a couple of those years approaching 30K cfs. High water for sure. So monitor the rain falling from the sky to understand what kind of water year we will truly have.

The 50 year average for peak water flows comes in at 14,082 cfs. Will we get there this year?

Missouri River April May Fly Fishing Forecast
Dearborn River Blown out Spring 2015

The snow that is on the ground on April 15th, tax day, is what the water managers base their  model upon. The entirety of the snowfall has already happened. Even if there is a couple of those big spring snows, it really does not effect the outcomes. Unless, it snows and snows and snows. Which can happen.

We have 95% of our historic average snow water equivalent right now. So we hope to roll on through the year at that level. Worst case scenario is 71%. Let’s hope for better than that. I hope we are delivered better than the 80% we saw last year 2016.

Again monitor the precipitation and watch the inflows and outflows. And watch this site. We do not provide occasional information here on this site. We feed you info daily! Honesty and transparency is our model educating you the angler of the info that is important. Not on our schedule, on your schedule. We will pass it on when we hear it!


Missouri River Bugs April & May

Midges: Through the  month into May. Not too good, not too consistent,  this year. But a few around to get your rod out. Fish clusters, individuals, or in conjunction with droppers. You can find the fish rising in pond like areas as well as seam lines. But mostly the soft water insides where the midges are buzzin’ around on the surface.

BWO’s: Mid April into mid June sometimes. But mostly through the end of May. The best and most consistent of the spring bugs. Afternoons are the time when you will see them come off. 2pm and later. They start on the lower river and move uphill. And they have started. So expect more bugs as the month moves on.

Seams, insides, and flats. Sipping trout love this insect. Mayflies are a Missouri River staple. The Blue Winged Olive is one of our favorites. 42F river temp is the start. We are at that now.

Patterns? Cripples, emergers, spinners and duns. Find the rivers best selection at Headhunters in Craig. Not only do we provide the honest info, more than occasionally, we have the best bug selection too. Stop in and see our expert shop staff for friendly bug information including the only free large format map on the river.

Not one BOW showing as of yet. Water temps too cool for them to show not he surface. But, dig around int he weeds and you will find them. Been subsurface for some time now. Patterns of that ilk should begin to influence your fly selection.

March Browns: Mid May. Look for them int he canyon first. A few runs harbor this great bug. A couple weeks on the outside is all we see. So be ready. Mottled winged March Browns are a mayfly that the fish go nuts over. Most keep this one under their hat. Specific patterns available at HH will help you fish with confidence. An Adams will get it done if needed.

Mother’s Day Caddis: Early to Mid May. Sometimes later. Mid Canon and below. X Caddis is all you need. A film fly is not a bad idea either. Big Brown Trout get amped up man. This is a great one and short lived too.

Missouri River April and May Weather

Variable. That is the definitive answer. As many, most, if not all of you know that you should come the Mo with your best spring arsenal. Rain jackets, snow clothing, gloves, neck protection, hand warmers, Thermos’, sunscreen, sun hats, multiple layers…whatever you can stuff in your pack or luggage!

Averages above. We van have rain, snow, sleet, wintry mix, wind, and sun too. Obviously the warmer weather warms the water. The cold ass weather cools it rapidly too. It takes far longer to increase water temps than it does to cool it off.


So come prepared for battle fishing here in Craig Montana. I know I have been ill prepared a few days already this spring. It takes a beating to remind me that summer is not here, and winter is not over.

This las week we have had 70F and windy sun all the way to 3″ of snow and sleet on the river. That is a wide range!

Missouri River April May Fly Fishing Forecast

And there you have it. Our current and future situation here on Montana’s Missouri River. A comprehensive look at the months ahead. We love spring here in downtown Craig. It brings life to us after a damn cold winter. Friends, anglers, smiles, laughter, and the smell of trout…whitefish too!

Give us a call at the shop on our Trout Hotline 8am for more info if this does cover enough information. And it may not. We love to talk about trout here at Headhunters Fly Shop. 406-235-3447

Headhunters is your source for entertainment, information, education and customer service on this one of a kind trout fishing resource.

April, birds, Bugs, Forecast, May, Populations, Trout, Water LEvels, Weather
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