This post is about likely summer and early fall water and fishing conditions, based on current snowpack and current predictions for late winter and early spring weather. As noted in the previous update, I’ll be posting updates on about a biweekly basis until about the middle of April, then weekly updates thereafter.
Since the previous update, weather has yo-yod from cold and snowy, particularly northwest of Yellowstone Park in the Gallatin drainage, to warm and dry. Currently we’re heading into a cold and snowy pattern that the long range weather forecasts predict will last through the 8-14 day period. Longer-range climatological models call for us to be right on the edge of cool/wet weather through March, and call for normal temperatures and above normal moisture through at least April.
In general, snowpack expressed as a percentage of average has remained basically flat in the two most important drainage in our operations area, the Upper Yellowstone River Basin in Wyoming (including Yellowstone Park and the headwaters south of the park) and the Yellowstone River basin in Montana. In these basins, snowpack is currently 139% of normal in the Upper Yellowstone Basin in Wyoming and 125% of normal in Montana. In all other basins, snowpack has increased since the last update. It is now at 127% of normal in the Madison-Gallatin drainage in YNP (an increase of 13 points since the last update) and ranges from 97% to 110% of normal in all other basins that impact our business in any way. These numbers are all between 5 points and 40 points higher than we were last season (most closer to 40 points), and are likewise substantially higher than things have stood at this point in theseason for any fishing season in the past 10 years with the exceptions of 2008, 2011, and 2014. The numbers are tracking closest to where they were in 2014.
Snowpack typically peaks in early April in the lowest-elevation areas besides valley floors and as late as early May in the extreme high-elevation areas. This means that we have between a month and two months to continue building overall snowpack. Current snowpack is now already near average seasonal peak depths at many high-elevation locations, and some in the Yellowstone basin inside YNP are already reporting snow depths deeper than they typically reach six weeks from now.
So what’s all of this mean for summer fishing???
Here it is in a nutshell…
We anticipate above average overall streamflow during the peak summer and early fall season on all waters in our operations area with the possible exception of the lower Gallatin River, coupled with late clearing from the spring melt on all waters that are subject to muddy water due to the melt. This basically means everything besides the Lower Madison and Missouri Rivers, the Paradise Vally spring creeks, and private lakes. Everything else will clear late and run normal to high through the summer, with cooler than normal water temperatures and less-spooky fish.
In general, the current snowpack that’s on the ground as well as what’s predicted for the remainder of late winter and early spring lead to excellent and consistent fishing ONCE THE WATER IN QUESTION DROPS OUT OF RUNOFF. This is a key distinction that visitors who have fished this area in the drought years this century (2001-2007, 2012, 2013, 2015, 2016) need to bear in mind. We have recieved many calls asking about floating the Yellowstone between June 20 and the end of the month. This period was epic the last two seasons, but it will almost certainly be completely impossible this year. A good rule of thumb is to shift your fishing dates back by two weeks if your trip falls prior to July 15 if you want comparable conditions to what we had in any of the drought years mentioned above. If you’ve fished with us from July-September in 2010 or 2014, these years are good analogs for the water conditions we expect.
Here are predicted clearing dates for the important waters in our operations area, as well as some general fishing notes.
The Yellowstone River Outside YNP: Will clear from runoff late, unless runoff starts two or more weeks early (late April). It will also clear at a higher-than-normal level. Streamflows should be excellent from July 15 or so through the remainder of the season, but float trips will be chancy at best from the onset of the runoff until AT LEAST July 4. We estimate the river will be floatable on July 4 to be at best 50/50. In 2014, the most comparable year to this one, we ran our first float trip on about July 8. We will not be accepting float trip reservations for trips between May 1 and July 14 until we have a better handle on the precise timing of runoff unless anglers are willing to float the Madison or do some other type of trip (walk, private lake, or jet boat) instead if the Yellowstone is unfishable. The onset of runoff will be a huge determining factor here. If it starts in late April, we’ll see a near-normal clearing date. If it starts as normal around May 5-10, we’ll see a slightly late opening (around July 10). If snowmelt is delayed until mid-late May (unlikely with current models) the river might not clear before July 20.
The Yellowstone Inside YNP: May be fishable as early as mid-June in the Grand Canyon, but early-mid July is a safer bet in the Black Canyon.
The Lamar Drainage: Cannot be counted on before mid-July. Good fishing should abound thereafter, with the fish seeing some relief from the extreme low flows of the past two summers.
The Firehole, Gibbon, and Madison: Should have extended seasons (into early July even for the Firehole) due to higher, cooler water. These will be our most important and best fisheries through most of June. The recent bump in snowpack in these drainages means that the Gibbon and Madison in particular may not be fishable until June 5-10, while the Firehole SHOULD be fishable when the park opens on May 27, though if there’s a lot of snow remaining in its basin on the opener and it decides to get warm and dump rain, that could be a problem even on the Firehole for a few days. On the flipside, it’s now at least possible the Madison and Gibbon will remain fishable through July.
Private Lakes: Those with natural inflow (the Story Lakes in particular) should see extended seasons. The others will depend on short-term weather. These lakes should not be impacted by runoff. The one exception is upper Story Lake which MIGHT be hard to access until about April 20 if April is cold. There’s a snow drift that can cover the road until this point if it stays cold long enough.
The Lower Madison: Since the upper Madison system in YNP has excellent snowpack, the lower Madison should run high and cool for longer than usual. This is a good thing, as this will be our float river through June this year. The upper Madison above Ennis Lake may be muddy through most of June.
The Missouri: Should see slightly above normal flows unless snowpack jumps drastically or we see a drastically early melt. The high snowpack in the upper Madison and Gallatin systems in YNP will be offset by the near-average snowpack in other drainage basins that feed the Missouri. Overall conditions will be good for Walter’s March-June power boat trips here.
Let me reiterate: we expect excellent to epic mid-late summer and early fall conditions in the Yellowstone drainage (including its tributaries like the Lamar) and early summer conditions in the Firehole, Madison, Gibbon, and Missouri systems. Early summer in the Yellowstone and Lamar drainages (before at least the beginning of July and probably a week later) will be far more limited. Since our busy season and usual better fishing is from the 4th of July through September, this is what we want to see.