Low Water and Weather – Outlook

I’ve long believed that extremely long periods of hot weather have a greater negative impact on trout and trout fishing than low water alone. We are heading into our normal “low flows” of summer. While we have enough to keep the flows above critical, we have none to spare. So far, we’ve escaped extreme hot weather of any duration.

The forecast for the rest of the month looks pretty good. No 90’s as of today. During lower water years it’s critical that we don’t experience too much hot (over 90 degrees) weather in June. We know we’re going to see hot air in July and early August, and don’t need the a jump start to increasing water temperatures in June. When we do, water temps increase too high too early, and the trout end of spending months instead of weeks in water temps at and above 68-70 degrees.

When this does happen – and it does – there is no reprieve for trout or anglers until the first freeze in the fall. So far, we’re looking OK.

As a fly fisherman, you hear a lot of talk every year about water flows, snowpack, etc. You don’t often hear talk about air temperatures, which have equal or greater impact when combined with low flows. And the Earth isn’t getting any cooler…

I don’t lose much sleep over the fact that warm water affects your fishing. That’s fishing. Sometimes it sucks. Sometimes entire summers suck.

But long periods of warm water are hard on the trout, and that does bother me. Right now the trout in the Missouri River are in excellent condition. They have had excellent feeding and spawning conditions, and the hatches have been excellent providing lots of calories. Over the last few weeks we’ve seen large Browns and Rainbows – that were a little slender a month ago – put on a tremendous amount of weight. An excellent indicator of the health of both the river and trout.

With no excess water and a hot summer, conditions for growth and health could quickly change. And not only does the weather affect the health of our adult population of Rainbows and Browns, it has a dramatic affect on the recruitment of juvenile trout.

While we won’t have any runoff to speak of this season, we do have enough water to keep the flows above critical. We just need Mother Nature to keep us under 90. That will keep water temperatures cool enough and the trout feeding and happy. Hopefully biting your flies as well.

Here’s the outlook for the rest of the summer (through August) and it does not look too bad. Central Montana is forecast to be near normal for both temperature and precipitation.

As for water, we are forecast to remain around 4000 CFS for the remainder of the summer. That would be great, and I hope it holds true. 4K and water temperatures that don’t get past the mid 60’s too often should keep our trout in great shape. While low flows are never good for the river, extreme air temperatures can be much worse.

The only thing that can offset hot air is more water. Unfortunately for Trout, we are living in a world that get’s drier and warmer every year.

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