Big Sky Country Snowpack Report - April, 2026
Hello fellow anglers of the Big Sky, and welcome to our April 2026 Snow Report. Late April is significant for us snowpack watchers because, typically, right about now is when we see our peak snow water equivalents. In other words, this is usually the moment when there is the most water stored in the snowpack for the year. As you’ll see from the deeper dive, our peaks came early this year. About a month early in fact. That means, from here on out, we’re hoping for cool and wet weather and more snow up high in order to maintain snowpack and slow the rate of decline of the snowpack, rather than to build up the maximum amount of stored water.
At risk of sounding like the proverbial broken record, this winter has been an extraordinary one in terms of warm temperatures. Across most of the west, this has been the warmest winter ever recorded. Simultaneously, and perhaps thankfully, we have received near to above average amounts of precipitation (more wet, than white) across most of the watersheds in our area and north in Montana, and we are still wondering how that will shape our summer season.
As for weather, we had awesome cold and wet conditions that brought a bunch of new snow to the mountains as well as town last week. Today and tomorrow are falling back in to the warm/hot category, and no doubt we will see some significant melting happen. But, cool and wet conditions return late Wednesday into Thursday and are forecast to stick around through the end of the 10-day forecast period! That will undoubtedly slow the rate of melt and likely even add to the existing snowpack. Good stuff for later in the summer as well as those out hunting for a Baetis hatch in the coming days.
Now, please join me as we dive deeper into the conditions in three of our favorite fishy watersheds. Note that the plots and number numbers are based on NRCS Snotel data and online mapping tools, and the number are from April 19th.
In the Madison watershed, Snow Water Equivalent (SWE) is at 67% of median for this date, down from 84% at the time of our last report. Annual precipitation is sitting at 101%. Yesterday was the typical date of Median Peak SWE in the Madison (21.1” of water). But this year we (presumably) hit our peak on March 18, at 14.4” of water, which is only 67% of the median peak value. Current SWE is 13.2”, which is 91.7% of this years peak value, snowing that we’ve lost some of the SWE to melting, but not a massive amount so far. How awesome was last week’s snowstorm? Watershed wide, the Madison gained nearly 1.5” of SWE, with up to 2.4” of SWE recorded at some sites according the Gallatin national Forest Avalanche Center.
Comparing the Black line (this winter) to the orange line (2024) and the light blue line (2015) you can see we are a bit above 2015 but a good bit below 2024. Hopefully the curve flattens or even climbs this coming week with the forecast conditions being cool and wet.
In the Yellowstone River Headwaters, SWE is at 87% of median, which is down quite a lot from 111% last report. Annual precipitation is sitting at 111%. April 24 is the typical date of Median Peak SWE in the Yellowstone Headwaters (21.7” of water). But this year we (presumably) hit our peak on March 19, at 21.0” of water, which is 97% of the median peak value. Current SWE is 19.2”, which is 91% of this years peak value, snowing that we’ve lost some of the SWE to melting, but not a massive amount so far.
Compared to the 2024 (orange line) and 2015 light blue line) things are good, but not great. The week of wet cool conditions ahead should be a big help.
In the Upper Henry’s Fork SWE is at 53% of median, down from 65% at the time of our last report, and hovering at or near record lows. Annual precipitation is much higher, at 97%. April 10 is the typical date of Median Peak SWE in the Upper Fork (27.2” of water). But this year we hit our peak on March 17, at 17.8” of water, which is only 67% of the median peak value. Current SWE is 13.9”, which is 78% of this years peak value, snowing that we’ve lost 22% of the SWE to melting so far. These are pretty sad snowpack conditions, folks, hanging out right there with the light blue line (2015). The bright side compared to 2015 is that we have actually gotten a good amount of water, just not as snow, and according to the Henry’s Fork Foundation’s Dr. Rob Van Kirk, Island Park Reservoir, which feeds the Fork all summer long, is on track to fill on May 10th.
So, there you have it, folks. We have been getting out fishing and enjoying the warm days, but are definitely looking forward to the cool and wet weather that’s on the way.
Until then, take care.
Matt and the BSA Crew
