May has been a return to spring conditions that we are accustomed to seeing here in the high country. A mix of hot weather, epic snowfall, and cool, wet spring fishing have characterized the past few weeks. It’s a dynamic time of year for fishing and doing your homework can pay off big time when planning your trip. Warm ambient air temperatures coupled with strong winds and dust-on-snow events got runoff going in a heavy fashion with most freestones in the state reaching near double average volumes in a short period of time. As shown, both the Roaring Fork and Eagle rivers ran heavy through the middle of the month. 

On May 20th we received our largest snowfall of the season to date with two feet of snow being recorded locally. As you can see, this snowfall put a stop to runoff and gifted us a week window of clarity on all of our freestones. This coincided with an emergence of salmonflies on the Upper Colorado through Memorial Day weekend, as well as a return to caddis on sunny days and baetis on cloudy days.  With another storm knocking on the doorstep, we expect the first week of June to enjoy some good conditions, before a return to runoff arrives. The first week of the Upper Colorado River salmonfly hatch was generally sparse and Memorial Day crowds were welcomed by a generally underwhelming emergence. This week with warming temperatures and turbidity under 10, conditions are prime for some fun action. Chasing salmonflies can be a rewarding but frustrating endeavor. 

A few things to remember…

1. Don’t be afraid to size down. A salmonfly is a big stonefly and while at the beginning of the hatch, the fish are very excited about large nymph and dry imitations, they often gorge themselves—much like a Labrador left to their own devices. While a large offering might get their attention towards the end of the hatch, they are more likely to eat a size down.
2. Find your mojo—Dead drifted flies are for technical tailwaters, not stonefly season. Every day and sometimes every fish is different, but adding the right wiggle to your fly makes it look more natural and is more likely to get an eat. I find that a small wiggle initiated by raising the rod tip followed by a mend and a quick settle through the pocket usually does the trick. This goes for nymphs as well as dries. 
3. Remember that there are more than just salmonflies in the system and the fish often get sick of orange, and another orange Fuzzy Wuzzy floating by them. Just like when you are forced to eat the same meal every day for weeks. Varying up your options and mixing in some golden stones and olive stones (especially in your dropper rigs) can help keep your rod bent.

Snowpack conditions vary widely, but on average, snowpack is solid at elevations above 10,000 ft. Below 10,000ft, snowpack is sparse, which makes predicting the runoff difficult since many of the SNOTEL sites used are below 10,000 ft. The big takeaway from the chart below is that where we have snow, the snowpack is generally near or above average, however, most of the lower elevation snow has already melted, which is skewing the percent of median numbers. Also interesting to note is that nearly all of the basins in the state had near average precipitation amounts for the season, but due to early melting and dust events, the current snowpack levels are significantly diminished. 

Stonefly season is upon us and in addition to salmonflies, we have been seeing some skwalas, olive stones, and it won’t be too long before yellow sally and golden stones are out and about. As the water rises, look for early season terrestrial food sources to become more important, like worms and craneflies.

What does all this mean for us? To me, based on 15 years of guiding, we’re looking at another few weeks of runoff on local freestone streams, with flows likely to peak toward the middle of the month. We are lucky that the snowfall this month has prolonged our melt. The Climate Prediction Center is calling for “normal” temperatures and precipitation for the next few weeks, which lead us into a near sense of “normal runoff” in the South Platte, Roaring Fork, Eagle, and Arkansas draininges.

The Upper Colorado River will continue to suffer from dewatering because Front Range water municipalities that control tributary reservoirs are both diverting water to their east slope infrastructure as well as holding water from downstream release to make sure reservoirs fill and they can satisfy downstream obligations later in the summer. We hope that as runoff abates later this month, the upper Colorado will begin to benefit from tailwater releases as forecasted. 

Turbidity

Turbidity gauges are all the rage now with 35 active gauges in the state. It has sure helped us guides make decisions ahead of time in terms of what kind of water conditions to expect. There has been a learning curve for all of us on how to interpret the data. It also appears that water temperature has an effect on the turbidity. For example, a recent turbidity reading of 12 when the water was 45 degrees showed 20” of visibility while when water temperature was 60 degrees, a turbidity reading of 12 had 12” of visibility.

We have distilled the turbidity to these general guidelines for us: