How We Read and Predict the San Juan River: The Story Behind Pagosa’s River Desk and Black Hat Hydrology Lab

I have been in the river business long enough to learn two things.

First, the San Juan River will do whatever it wants.

Second, everyone assumes I know what that will be.

For more than 20 years, I could not show my face in a Pagosa coffee shop, sit down on a bar stool or make it through a conversation between the first winter storm and the end of spring runoff without someone asking me to predict the river.

“How’s the snowpack?”

“Are we going to have a good rafting year?”

“When will the river peak?”

“When will tubing start?”

“Will there still be enough water when my family gets here?”

Sometimes the person asking had a vacation planned months away and wanted to know whether the family should expect a raft, a tube or a walk through a mostly exposed riverbed. Because I owned the river company, I was apparently presumed to have a private line to the snow gods.

The uncomfortable truth was that I usually did have a pretty good answer.

Not a certain answer. Anyone offering certainty about a free-flowing mountain river should probably be moved a few stools farther down the bar. But after decades of watching the same watershed, I could usually tell whether we were building toward a big season, an average season or a mild year when locals and visitors needed to get on the rafts early instead of waiting for warm June weather.

Those answers came from experience, but they were never purely “gut instinct.”

My gut had browser tabs.

How We Predicted the River Before the River Desk

The old morning ritual involved opening the USGS river gauge, checking the two headwater SNOTEL stations, reading the official river forecast, looking at the weather in town and in the mountains, comparing the current year with previous seasons and trying to remember what happened the last time the numbers looked similar.

Then there were the things that did not fit neatly into a government chart.

How much dust was layered through the snowpack? Had the nights stopped freezing at 10,000 feet? Was the river rising faster each afternoon? How much snow remained in the shaded trees? Had the jumping trout begun emerging from the snowfield on Blackhead Peak? Were the snow geese appearing on Quartz Ridge?

Finally, I combined all of that with 20-plus years of memory and made a call.

It sounds charmingly old-school now. At the time, it mostly meant too many browser tabs, too much coffee and the knowledge that employees, guests and other business owners were waiting for me to say something useful.

The answer mattered far beyond bar-stool bragging rights.

It affected when we hired and trained guides, how many rafts we prepared, when we opened reservation calendars, how we scheduled shuttle drivers, what equipment we purchased and when the whole operation shifted from rafting to tubing and lake rentals.

A mild rafting season means encouraging people to come in May while the water is still fun instead of waiting until the traditional June vacation window. A strong season means preparing more guides, rafts and shuttle capacity—and reminding locals that this may be the year they should not miss.

A normal water year generally moves from higher spring rafting flows into warm-weather tubing flows. The below-tubing conditions we sometimes see late in a dry summer are not a normal middle stage of the season. They are the tail end of the water supply, an unusually dry year or a stretch waiting for widespread monsoon rain.

For years, I was taking the same information, processing it mostly inside my own head and handing out an answer.

The obvious question eventually became: Why had nobody built a single Pagosa-specific tool that did this?

Building the Tool We Could Never Find

Pagosa Outside has always evolved by looking for the missing piece.

If a better piece of river gear does not exist, we find one or convince a manufacturer to invent it. If a trip can run more smoothly, we change the logistics. If guests keep struggling with the same confusing question, we try to build a clearer answer.

The Pagosa Outside River Desk grew from that approach.

I had the questions, the local history, the activity thresholds and the ideas about how everything should fit together. A low water season helped turn those ideas, formulas and decades of observations into a working public tool.

The River Desk became a digital version of the process we had been doing behind the scenes every morning—only more organized, more consistent and considerably less dependent on whether I had finished my second cup of coffee.

It combines:

• Live San Juan River flow

• The 24-hour average and direction

• Historical flow for the same date

• River temperature

• Official short-term forecasts

• Town and headwater weather

• Upper San Juan and Wolf Creek Summit snowpack

• The water-year hydrograph

• Pagosa-specific rafting and tubing ranges

• The activities that make sense under current conditions

More importantly, it translates the data into the question visitors are actually trying to answer:

What can we do on the water in Pagosa today?

The River Gauge Tells You How Much Water There Is. The Desk Tells You What It Means.

The USGS San Juan River gauge is one of the most important sources behind the River Desk.

It reports flow in cubic feet per second. What it does not tell an unfamiliar visitor is whether that number means rafting, tubing, paddleboarding or finding something completely different to do.

Most people do not search for “the instantaneous discharge of USGS gauge 09342500.”

They search for things like:

• Is the Pagosa River running?

• Is the river open in Pagosa Springs?

• Is the water high enough to float?

• Can we tube the river today?

• Are tubes running in Pagosa?

• Can I raft Pagosa Springs in July?

• Is the river too low?

• How deep is the river?

• Should we book a raft or a tube?

• What is the water level in Pagosa right now?

Some of those questions are technically wrong. There is no “Pagosa River,” the river does not open and close like a ski lift, and one CFS reading does not tell you the depth of every rapid.

They are still perfectly reasonable questions.

The job of the River Desk is to understand what people mean and give them a useful answer.

What Today’s Flow Means for Rafting and Tubing

The current-conditions section of the River Desk places the live gauge reading on a nonlinear rafting-and-tubing dial.

That matters because the two activities occupy different parts of the river season.

Pagosa Outside’s general tubing range is 30–399 CFS. The favorite flows for many tubers are around 90–180 CFS. The river becomes faster and rowdier through the upper 100s and 200s, while 300–399 CFS can create high-water tubing when the weather and water are warm enough.

Around 400 CFS, the San Juan generally begins shifting toward rafting.

The three Pagosa Outside rafting trips also require different amounts of water:

• Splash & Dash generally begins around 300 CFS

• Mesa Canyon generally requires about 600 CFS

• West Fork generally requires about 800 CFS

That is why “Can we raft?” cannot always be answered with one universal number. A flow that supports a downtown Splash & Dash may not provide enough water for Mesa Canyon or the West Fork.

The Desk shows the current flow, recent direction, historical average, water temperature and trip-specific ranges together. Instead of making a visitor interpret the gauge, it identifies which river experiences fit the water right now.

What Is the River Likely to Do Next?

A single gauge reading tells us what has already reached Pagosa Springs.

The short-term River Desk forecast adds seven days of measured flow, the official seven-day river forecast and a weather-aware outlook through day 10.

During spring runoff, the important questions are often:

• How warm will it be in the headwaters?

• Will the nights remain below freezing?

• How much mountain snow remains?

• Is the river accelerating or flattening?

• Will an approaching cold front preserve some water for later?

During summer, the questions change:

• Is rain actually forecast in the headwaters?

• Will it be widespread or isolated?

• How wet is the watershed before the storm arrives?

• How have similar summer storms affected the river?

• When might the response reach the Pagosa gauge?

A thunderstorm over downtown may wet the sidewalk without materially changing the river. A widespread storm over the East Fork, West Fork and surrounding headwaters can produce an entirely different result.

The Desk shows those different stories without pretending the river will hit one exact CFS at one exact future hour.

The Seasonal Question Is Bigger Than Today’s Flow

The seasonal River Desk outlook follows the watershed through the water year.

During winter, it watches year-to-date snow-water equivalent at the Upper San Juan and Wolf Creek Summit SNOTEL stations. Those readings estimate how much water is being stored in the mountain snowpack and whether the seasonal water supply is building ahead of, near or behind normal.

During spring, the Desk shifts toward peak snowpack, remaining snow, temperatures, dust and runoff timing. It begins estimating the general strength of the rafting season and the likely rafting-to-tubing transition.

That season-strength call is important.

A strong year may produce high, exciting water that locals should make a point not to miss. An average year is still a perfectly good rafting season. A mild year means the fun high water may come and go earlier, requiring us to tell guests honestly that May could be the time to raft rather than waiting for the warmer days of June.

By summer, the stored mountain snow has usually melted and the River Desk changes its focus again. Native flow, monsoon rain, tubing conditions and the completed water-year hydrograph become the story.

This longer view helps visitors plan, but it also guides real operating decisions inside Pagosa Outside.

It influences hiring, training, equipment preparation, guide schedules, shuttle capacity, marketing and the timing of our shift among rafting, tubing and lake rentals.

The forecast does not make those decisions for us. It just gives us a more consistent foundation for making them.

The Toughest Question Our Front Desk Has to Answer

The River Desk solved much of the “What is the river doing now?” problem.

It did not solve the hardest question our front desk hears:

“What will the river be doing when we get there?”

Someone calls in March with a family trip planned for June 21. They do not care what the gauge reads today. They want to know whether to reserve a raft.

Someone else is arriving in July and asks whether there will be enough water to tube.

A wedding group is coming in six weeks. A family reunion has one free afternoon. Grandparents are trying to choose an activity for twelve people who have already booked flights and a vacation rental.

Our staff could explain normal seasonal patterns, but eventually everyone looked toward me.

Apparently, 30+ years in the river business meant I should know what the San Juan would be doing on a particular Tuesday 53 days from now.

That pressure created Ask the Black Hat.

A visitor selects a date from one to 90 days in the future. The Lab estimates a possible flow range and then translates it into the odds of reaching the flows associated with:

• Tubing at 30–399 CFS

• Splash & Dash rafting at 300 CFS

• Mesa Canyon rafting at 600 CFS

• West Fork rafting at 800 CFS

This is the function I wish our front desk had possessed for the past two decades.

It does not promise that a specific trip will operate. It gives the staff and the guest a more informed answer than “Well, normally…”

It also turns an instinctive prediction into something measurable. The formula provides the same answer to the same question regardless of who is working, whether the shop is busy or how optimistic I happen to feel that morning.

Why We Put the Black Hat On It

Once we began turning our historical decision process into formulas, the next question was irresistible:

Could we use the same information to make longer-range predictions—and then let the river publicly grade them?

That became the Black Hat Hydrology Lab.

The Lab combines approximately 25 years of Pagosa river and snowpack history with live gauge readings, current snowpack, forecast weather, seasonal timing and the relationships that held up during testing.

Its motto is:

Questionable hats. Serious data. Experimental forecasts.

The Black Hat name gives us room to experiment without pretending that we have finally defeated hydrology. The formulas can spark, rattle, miss a prediction and get rebuilt. Mother Nature remains unimpressed.

The Eight Questions Everyone Expected Me to Answer

The Lab’s eight official predictions did not come from an academic list of hydrology exercises.

They came from coffee shops, bar stools, phone calls, staff meetings and conversations I have been having for more than 20 years.

They are the questions everyone assumed I should know because I was the person in the community with the most to gain—or lose—from the answers.

1. When will the first lasting headwater snowpack arrive?

This is the first sign that the new water year has begun building something real. An early storm can disappear. We wanted to identify the first snow that arrives and stays.

2. How much water will the headwater snowpack hold at its seasonal peak?

Peak snow-water equivalent is the starting point for nearly every spring river conversation. It tells us how much water is stored in the snow before temperature, dust and weather decide how quickly to release it.

3. When will the river first reach 400 CFS?

Four hundred CFS represents a meaningful seasonal change. It signals the official beginning of Pagosa’s rafting season and the beginning of more dependable rafting water.

4. How strong will the May–June rafting season be?

This is the practical “What kind of rafting year are we having?” question.

Will it be a strong, exciting year that locals should not miss? Will it be an average year—which is just fine? Or will it be a mild season when guests need to get on the river early instead of waiting for their traditional June outing?

5. When and how high will the spring runoff peak?

This is the championship round of Pagosa river guessing.

Everyone wants a date and a CFS. The river rarely feels obligated to provide either on schedule.

6. How many rafting-flow days will the season produce?

A single peak does not describe an operating season. The Lab counts days at the thresholds that matter for Splash & Dash, Mesa Canyon and West Fork.

That tells us far more about the usable rafting season than one impressive high-water reading.

7. When will tubing season open?

Our tubing season does not begin simply because one gauge reading briefly falls below 400 CFS. The river needs to make a real post-peak transition into the tubing range.

This prediction addresses one of Pagosa Outside’s most awkward transitions. If we knew exactly when rafting would end and tubing would begin, booking, scheduling and marketing would be far less of a headache—and far less uncertain.

8. How many tubing-range days will the season produce?

The final prediction measures the length of the tubing opportunity between May 1 and Labor Day. It separately records days lost above rafting flows and days lost below 30 CFS.

In a normal year, the river generally transitions from rafting into tubing. Below-tubing days become a larger story during unusually mild runoff years, drought or the late-season period after the normal water supply has faded.

Together, the eight questions cover the full seasonal arc: the first lasting snow, peak snow storage, the arrival of rafting water, the strength and peak of runoff, the number of usable rafting days, the tubing transition and the length of the tubing season.

They are measurable questions with finish lines. That means the Lab cannot quietly revise its memory after the river proves it wrong.

Mother Nature Keeps the Score

The Lab locks each seasonal prediction on a defined issue date.

Once it is locked, it stays visible. When the finish line arrives, the prediction receives a Hit, Miss or Pending result on the PO Black Hat Lab vs Mother Nature scoreboard.

That public scoring was important to me.

Humans are very good at remembering the prediction we nailed and developing sudden amnesia about the one that missed by three weeks and 1,000 CFS.

The scoreboard removes that temptation.

The Lab’s methods were tested chronologically against historical seasons, using only information that would have been available at the time of each prediction. The 30-, 60- and 90-day ranges were also calibrated against historical forecast errors.

The testing does not make the Lab infallible. It makes it accountable.

That is a much more useful goal.

The Mountain Still Gets a Vote

The Lab uses data and formulas, but we have not thrown away the observations that helped us understand the watershed in the first place.

Local educator and river observer Josh Kurz has spent years studying the relationships among snowpack, dust, temperature and San Juan River runoff. His annual Predicting the Peak posts helped frame many of the same questions the Lab now attempts to test.

Josh also documented how dust helped accelerate the unusually early 2022 spring runoff. Dark dust absorbs more solar energy than clean snow, so a seemingly normal snowpack can melt much faster than its total SWE would suggest.

Then there are the local snowfield indicators.

As the snow melts on Blackhead Peak, a shape resembling a jumping trout emerges from the snowfield. Nearby, snowfield geese appear on Quartz Ridge. Local observers have used their appearance as signs that peak runoff has passed and the San Juan is beginning its decline.

Josh recorded the story—and the trout’s previous identification as a dolphin—in Signs in the Snow.

The trout and geese are not replacing SNOTEL sites. They are visible evidence of how much snow remains across the mountain landscape.

The Lab is strongest when formulas remain connected to what is actually happening outside.

Why Make Our River Brain Public?

The River Desk is my public brain dump.

It is also an affirmation of what Pagosa Outside has been doing behind the scenes for more than 20 years.

We have always gathered the best information we could find, added what we were seeing on the river and in the mountains, and tried to give guests an honest answer.

The Desk makes that process visible.

The Black Hat Lab takes it one step farther. It turns our more questionable longer-range calls into public, testable experiments.

We could have kept all of this inside the shop. But the questions were never limited to our paying customers.

Locals want to know when to raft. Visitors want to know whether to pack for tubing. Fishermen watch the temperature and flow. Property owners worry about high water. Businesses plan around the spring and summer season. People simply want to understand the river running through town.

Making the information public serves all of them.

It also reflects a larger Pagosa Outside philosophy: when the tool we need does not exist—or the useful pieces are scattered across the internet—we invent a better one.

Then we keep learning from it.

Which Tool Should You Use?

Use the River Desk when you want to know what the San Juan is doing now, which activities fit the current flow and what the official short-term outlook shows.

Use the Live Seasonal Watch to follow the river question currently unfolding.

Use the 30-, 60- and 90-day forecast suite to see the Lab’s experimental longer-range flow estimates.

Use Ask the Black Hat when you have a particular vacation date and want to know whether the flow is more likely to fit a tube or one of our rafting trips.

The shortest explanation is:

The River Desk helps you decide what to do. The Black Hat Lab shows what we are still trying to learn.

Frequently Asked Pagosa River Questions

Is the Pagosa River running right now?

The river through Pagosa Springs is the San Juan River. It flows year-round, but the amount of water and the activities it supports change dramatically. Check the live River Desk for the current flow and activity recommendation.

Is the river open in Pagosa Springs?

The river itself does not have a universal open or closed status. Rafting and tubing availability depends on flow, water temperature, weather, debris, access and the specific trip. The River Desk shows which Pagosa Outside activities currently fit the river.

Are tubes running in Pagosa Springs today?

Check the current tubing gauge and activity status on the River Desk. Pagosa Outside generally tubes between 30 and 399 CFS, with 90–180 CFS being a favorite range for many guests.

Is the San Juan River high enough to float?

That depends on what you mean by “float.” Rafts, tubes, kayaks and paddleboards need different conditions. The River Desk translates the current CFS into the craft and activity that best fit the water.

Should I book rafting or tubing in Pagosa Springs?

Rafting generally occupies the higher spring runoff period. Tubing usually follows as the river falls below approximately 400 CFS and warms. Use Ask the Black Hat for an experimental future-date estimate, then check the River Desk and trip calendars as your date approaches.

Can we raft in Pagosa Springs in July?

Sometimes, but rafting is most dependable during May and June. A strong snow year or widespread monsoon rain can produce July rafting flows. Many years transition to tubing by then.

Can we tube in Pagosa Springs in May or June?

Possibly. Tubing begins after the spring peak when the river settles into the 30–399 CFS range and conditions fit the activity. A mild runoff year can produce an early transition, while a strong year may remain in rafting flows longer.

How deep is the San Juan River in Pagosa Springs?

There is no single river depth. Depth changes from one channel, rapid and pool to another. CFS measures water volume, not universal depth. The River Desk uses flow ranges and local experience to explain what the river is likely to feel like.

What is the current water level in Pagosa Springs?

River flow is reported in cubic feet per second rather than one lake-style water-level number. The current CFS, 24-hour direction and historical comparison appear on the River Desk.

What does CFS mean?

CFS means cubic feet per second. It measures how much water passes the gauge every second. One CFS equals approximately 7.5 gallons per second.

What flow is good for tubing in Pagosa Springs?

Pagosa Outside generally operates tubing between 30 and 399 CFS. Flows of 30–90 CFS are shallow, 90–180 CFS are a favorite range, the upper 100s and 200s become faster, and 300–399 CFS can produce rowdy high-water tubing.

What flow is needed for rafting in Pagosa Springs?

Splash & Dash generally begins around 300 CFS, Mesa Canyon around 600 CFS and West Fork around 800 CFS. The different trips require different amounts of water.

When will the San Juan River peak?

Peak runoff most often occurs during spring snowmelt, but the exact date and flow depend on snowpack, temperature, dust and weather. The Black Hat Lab makes and publicly scores an experimental peak prediction each year.

Will there be enough river water during my Pagosa vacation?

Nobody can guarantee a naturally flowing river months ahead. Ask the Black Hat provides an experimental estimate for dates up to 90 days away. The River Desk becomes the better resource as your date approaches.

What is the best time of year to raft or tube the San Juan River in Pagosa Springs?

Rafting is generally best during spring runoff, most often from May through June, when snowmelt raises the San Juan River. Tubing usually becomes more favorable after the river drops below approximately 400 CFS and the water warms, often from late June through summer. Conditions vary each year, so check the Pagosa Outside River Desk for current flow, water temperature and activity recommendations before planning your trip.

An Ongoing Pagosa Experiment

The San Juan will never become completely predictable.

Late snow can rebuild a fading winter. Dust can dramatically accelerate the melt. A cold May can preserve runoff, while several hot nights can release it in a hurry. A summer storm can completely miss the headwaters—or temporarily bring the river back to life.

That uncertainty is part of running a river business.

For more than 20 years, I made the best calls I could with scattered data, local observation, historical memory and experience. The River Desk and Black Hat Lab take that same process, organize it, test it and make it available to everyone.

They are not the end of our education.

They are the latest step in Pagosa Outside’s continuing effort to find, develop and invent the tools that help us do our jobs better and give our guests a better day on the water.

We will keep refining the formulas, scoring the predictions and learning from the misses.

We will also keep watching for the jumping trout on Blackhead Peak and the geese on Quartz Ridge.

Some parts of the old forecasting system are simply too Pagosa to automate.