With March now in the rear-view mirror, I figured it was a good time to offer an update on Colorado’s statewide snowpack, as well as our pending spring runoff. March 2019 was the 2nd coldest March on record (the coldest was in 1906), and produced record snow accumulations in the first half of the month that now has our statewide snowpack at 132% of average, the 2nd highest level we’ve seen in 34 years (1993 was the highest). This is tremendous news as we head into spring, particularly when considering the abysmal snowpack we had this time last year.
While everyone is rejoicing at the abundance of water stored in our state’s higher elevations, questions are funneling in as to how this is going to affect our pending runoff. As I’ve noted countless times, this is a loaded question, as there are so many variables one must consider. I’ll do my best to break this down, and offer some sort of answer for us all to work off of. In Colorado, the median peak runoff based on a 30-year average is April 10th. This means that on this date, our statewide snowpack is at its greatest level, and from there we can expect it to fall. While this doesn’t signal the beginning of runoff, it does allow our water managers to begin planning on how they intend on moving water around our state's reservoirs.
When you look at the chart below, you’ll notice that we are well above where we were this time last year, and we are also trending towards peak snowpack levels.
And while it does appear that we have peaked for 2019 ( Snowpack has been on a decline due to warm high country temperatures), There is a pending Winter Storm Warning in effect for most of the state for today through tomorrow night. Considering that April is also one of the snowier months of the year, I think it’s fair to assume that we have either seen our snowpack peak or that it will peak in the coming week to 10 days.
We can further explore the conditions in the different river basins statewide. The following graphic notes the current statewide snowpack as of April 1, 2019, but also provides comparisons to last year, and the median average.
As you can see, we are well above average in every single river basin, and nearly 3x Higher than last years average in the southwestern portion of the state. So with our snowpack almost at its annual peak and well above average, it’s up to mother nature to determine how fast, or slow the meltoff will last. Keep in mind that runoff tends to come in multiple stages, and not all of these stages mean bad things for fishermen. The first melt we will see is what I like to call “valley melt”. This typically starts to occur right after peak snowpack, and effects areas below 10,000’. This is typically where the snowpack is the lightest and offers our rivers and streams a nice reminder of what’s to come. During this time, most free-stone rivers will break free from their winter slumber, and resident trout begin bulking up on food prior to the bigger runoff event. Fishing during this time can be outstanding, particularly on freestone rivers. The key thing to remember is water temps, as the fish will be most active during the afternoon hours when the water is at its warmest.
The next runoff cycle is what I call “the main event”, where we see snow above 10,000’ melt. You know that this is happening when valley temperatures are over 70 degrees, meaning temps at higher elevations are now at a level where melt off can occur. Once we’ve reached this point, we’re ideally hoping for continuous warm weather to keep the runoff going. One thing to be watchful for is rain, as warm, high elevation, temperatures combined with significant moisture could lead to flooding at lower elevations. From a fishing standpoint, it is imperative during the main event that you be mindful of river flows, and always remember how powerful rivers are during this time. Fishing can be productive when the rivers are high, but anglers need to focus their efforts on fishing along the banks and never getting into the water.
So until my magic eight ball is back from the shop, the proceeding runoff prediction will have to suffice. It’s important to remember that no matter how fast or slow our snowpack comes down, it only means great things for the summer ahead. Cold and clean water will be abundant, and annual flushes help ensure the health of the fish and other aquatic life. Reservoirs will be at, or above capacity, ensuring great flows throughout our states tailwater fisheries. So while we all may be sidelined from our favorite freestone rivers for a short period, the stillwater and tailwater fishing during this time should be exceptional.
Cliff notes: get ready for a phenomenal summer of fly fishing in Colorado!
I’ll be sure to provide updates and things continue to evolve, but in the interim get out on the water and enjoy everything the Fifth Season has to offer.
Owner, Trouts Fly Fishing