The mountains store it. The San Juan tells the rest.
Explore 39 water years of snowpack, spring runoff and summer rain. Put seasons side by side, bring in this year’s readings, and see what happened after a familiar-looking start.
1.0.0
SNOW & FLOW EXPLORER
Different years. The same calendar.
Preparing the current-season comparison…
Hover or tap either graph to read both. Arrow keys move one date at a time.
The plots share a calendar. River flow uses a log scale in CFS; snow water equivalent uses a linear scale in inches. SWE is the daily average of Upper San Juan and Wolf Creek Summit. Gaps stay visible; missing data never becomes zero.
AT THE SAME POINT IN THE SEASON
The comparison
Water year
Flow on date
SWE on date
Peak SWE so far
Next 30 days: historic mean flow
“Next 30 days” shows what actually followed in a past season, where at least 25 daily readings are available. It stays blank for the current season. These comparisons inform a judgment; they are not a new Black Hat forecast.
One season, eight answers
HISTORIC RIVER ARCHIVE · 1988–2026
Mother Nature’s answers, year by year
This is the Lab’s fourth standalone section: the completed river record, not a prediction scoreboard. Choose a year for its plain-language season story, October–September snow-and-flow hydrograph and Mother Nature’s answer to all eight questions the Black Hat now predicts.
LOADING THE ARCHIVE
Building the historic season catalog…
The Lab is turning the gauge record into a river story.
MOTHER NATURE’S EIGHT ANSWERS
The season behind the scoreboard
These are the measurable outcomes the annual game tries to call before the river supplies them.
1 · WHEN DID SNOW STICK?--
The first seven-day start with at least 1 inch of average SWE and no day below 0.5 inch.
2 · HOW MUCH WATER DID THE SNOWPACK HOLD?--
Each year’s finished peak compared with the average annual peak.
3 · WHEN DID RAFTING WATER ARRIVE?--
First daily mean at 400 CFS or more.
4 · WHAT KIND OF RAFTING SEASON WAS IT?--
The full May–June hydrograph supplies the season grade.
5 · WHEN AND HOW HIGH DID RUNOFF PEAK?--
Highest instantaneous Pagosa gauge reading, with local time.
6 · HOW LONG DID RAFTING WATER LAST?--
Operating-season days at 300+, 600+ and 800+ CFS.
7 · WHEN DID TUBING WATER ARRIVE?--
Recorded opening when available; otherwise the gauge handoff.
8 · HOW LONG DID TUBING WATER LAST?--
Days at 30–399 CFS after opening through the Sunday before Labor Day.
OPEN THE HYDROLOGY LOGDaily means, middle-water range and exact rules
DAILY-MEAN SPRING PEAK--MAY–JUNE AVERAGE--FIRST DAILY 400+--DAYS AT 600+--GAUGE HANDOFF BELOW 400--SPRING TEMPERATURE--SNOW GAIN AFTER APRIL 1--
The historic graph and counts use archived daily-mean flow at the Pagosa USGS gauge. Peak SWE is the daily average of Upper San Juan and Wolf Creek Summit. Historic peak percentage compares each finished year’s peak with the 1991–2020 average annual peak of 31.9 inches; the live winter Lab continues to use date-to-date percent of normal. Instantaneous peak is separate from the daily-mean hydrograph; the game’s spring-peak card uses the instantaneous crest.
The archive translates gauge and SNOTEL records into recreation language. “Rafting day” means a May 1–Labor Day daily mean of 300+ CFS; bigger-water counts use 600+ and 800+. The monsoon epilogue counts July–August days back at 300+ after tubing water arrived. These describe available water—not a trip log, staffing record or guarantee that an activity operated.
