An Ode to Pre-Runoff Windows

April is a glorious “under-the-radar” month on my home river. While so many fly fishers focus on tailwaters further south in Utah, Colorado, and New Mexico, the lucky few that know of this time on the Snake River in Wyoming understand how special it is. Sure, the weather is variable, with cold rains or event snowstorms that dump a few inches on the valley floor not necessarily uncommon. But the Snake offers dry fly action that rivals what we get in the more popular months of late summer and through autumn.

Midges, winter stones, and blue-winged olives ring in the new first couple of weeks of April. The second half of the month brings about a skwala hatch that is matched by only a few other streams in the Rocky Mountain West. It hits its stride in the last few days of April and then gains strength in the first week of May before finally dwindling to a fizzle. It might as well – May is when our runoff is in full swing, and the Snake can be thick and muddy enough to almost plow.

But things are changing on the Snake as much as they are changing everywhere in the World of fly fishing. Climate change deniers are going to be offended by my take regarding what is going on. The simple fact of the matter is that all the indicators we look at suggest a runoff that is starting earlier with each passing few years. There are 20 more frost-free days now than there were 30 years ago. The number of mid-winter overnight lows that are below -30 have dwindled to the point that we are shocked and surprised to see one occur, let alone several in a row. And the biggest change of all - the rate at which our runoff starts earlier every year.

My father guided on our area rivers from 1959 until his death in 2003. He used to say that “the runoff starts on May 10th every year. And if it hasn’t started on May 10th, it will start on the 11th.” A lot of those older, long tenured guys said that when I started guiding back in the early 1990s. And really, that is kind of the way it actually was.

Today, it is a something really special to see the runoff start in the first week of May. It happens every now and then, but for the most part, it begins sometime in the last week of April. Last year, it started on April 21st. This year, we began to see our first signs of it on April 19th.

If global warming is not happening, there is no doubt that “local” warming sure as hell is. At least it is in my part of the World.

Now are there upsides to all of this? Yes. Temps are warmer than ever in early April, and that means even more intense dry fly fishing with #14 to #20 midges and BWOs than my father every really experienced with any consistency. And March has been lights out with streamers and dries and nymphs. In fact, March is becoming what April was. And the runoff is ending earlier on average, meaning that we can fish those late June hatches that were not in the cards 30-plus years ago except on rare occasions.

When the Snake is in full runoff, guides are not starving. The upper Green is less than an hour away. So is the South Fork of the Snake in Idaho, a storied dry fly tailwater. The lakes of Yellowstone National Park are a bit of a longer drive, but they can be epic when they open on

Memorial Day Weekend.

Nonetheless, I miss what we used to have on the Snake before runoff each April and May. There was something special about tossing #8 to #10 skwala imitations for seven hours straight and getting eats over and over and over again.

And every little now and then, when winter lasts a little longer and spring is a little cooler, those days are in the cards. I just want a lot more of them.