One river, one day, two very different answers.
On the morning of Oct 2 our Eagle River card read the Red Cliff gauge: 7 cfs. Taken at face value, that is a river not worth the drive. But Red Cliff is a headwater gauge with a base flow of about 11 cfs, well upstream of the water most people fish. That evening, with Scores v2 in production, the card read the gauge near Minturn, on water many anglers fish: 46 cfs, right where it usually is in early October.
Scores v2 moved the Eagle to the Minturn gauge, which has a daily record from 1989 and a water temperature sensor, and judges it only against its own history. A shop that posts this card shows its customers the river they actually fish.
Five inputs, each one you can check.
Each part of the score comes from public, published sources, and a missing input is left out and lowers the confidence. Nothing is filled in with a default.
Flow against its own history
Today's flow is ranked against the daily flows recorded at the same gauge for the same date, pooled over a week either side, from 1996 to 2025. The classes follow the USGS WaterWatch method: much below normal under the 10th percentile, normal from the 25th to the 75th, much above over the 90th. 8 of the 10 gauges that reported on Oct 2 (the Piney, the 11th, was dark) carry the full 30 years; Gore Creek has 27 and Tarryall 23. Tailwaters below dams fish well at low, steady releases, so they lose less for low flow than freestone streams do. On the cards, "% of average" is today's flow as a share of the daily average for the date, the same measure as the CPW 50% line.
Water temperature
Where the gauge has a sensor. Trout feed best from about 50 to 60°F, and the U.S. Fish and Wildlife Service habitat model puts brown trout growth at its best from 54 to 66°F.
Weather at the river
The National Weather Service forecast grid at the gauge itself: wind and gusts in daylight, the chance of rain and of thunder, and cloud cover, which earns credit in blue-winged olive season.
Flow stability
The change over 24 and 72 hours. Steady or gently falling water scores best, and a jump of 40% or more in a day is read as off-color water. The gauges do not measure clarity, so this is labeled an inference.
Hatch window
Whether a major hatch is in its usual window, from published charts: Big Y Fly Co for the Blue, Cast and Fly for the South Platte, Hooked and Executive Angler for the Eagle and Gore Creek. It is a calendar, not a sighting, and the card says so.
Some conditions cap the score, however good the rest looks.
These rules run before anything else. When one applies, the card says which one, in plain words.
On Oct 2 the Blue below Dillon sat at 50% of its daily average and scored 6.5, the low-flow cap for a tailwater. Gore Creek, a freestone at 34%, scored 5.5, the cap for a freestone.
- Water at 71°F or warmer (daily maximum)
- Score capped at 1, with "Do not fish." Colorado Parks and Wildlife lists a daily maximum above 71°F as one of the criteria for an emergency fishing closure (2 CCR 406-1-104 F.1). Our cap starts at 71°F itself.
- Water at 68°F or warmer
- Capped at 4, with "Fish early only, keep fish wet." This is our own line, set below CPW's on purpose.
- Flow at or below 50% of the daily average for the date
- An advisory to handle fish gently, and a cap of 5.5 on freestones and 6.5 on tailwaters, or 5 if the water is also 65°F or warmer. CPW lists flows at 50% or less of the daily average flow as an emergency closure criterion.
- Flow up 40% or more in 24 hours
- Capped at 5, with a note to expect off-color water.
- Freestone flow at 4 times its own base flow
- Treated as snowmelt runoff and capped at 4.
- Thunder chance of 40% or more in daylight
- A lightning advisory on the card.
- October and November on brown trout water
- A reminder that browns are spawning and to stay off the gravel beds. It does not change the score.
Every score says why, and how sure it is.
The card carries the main reason in one sentence and a confidence level. The river page lists every factor, marked as helping, hurting or neutral. This is the full list for the Blue on Oct 2.
Why this score: Blue River, 6.5/10
- Flow 54 cfs is much below normal for Oct 2 (5th percentile, 1996-2025; median 104 cfs, 50% of average).
- Holding steady (0% over 24 h).
- Water 44°F (43-46°F over 24 h), cool and building.
- Light wind, gusts to 14 mph, mostly sunny.
- In the usual window: Midges, Mysis shrimp, BWO. Source: Big Y Fly Co Blue River hatch chart.
- The agency has reported exactly 53.9 cfs every day for several weeks (provisional data). A steady reservoir release looks like this, and so does a stuck sensor, so confidence is reduced.
Confidence multiplies three things: how much of the score rests on measured data, how fresh the reading is, and how long the gauge's record runs. Data checks, like the flat-line rule below, can lower it further. It reads High from 0.8, Medium from 0.6 to 0.79 and Low under 0.6. The Blue has every input and a 30-year record, and its confidence still drops to 85% because of the flat-line check below.
When a gauge goes dark or looks stuck, we say so.
Agency data is provisional, sensors fail and seasonal gauges shut off. A score built on a bad reading would look just as confident as a good one, so the rules for missing and suspicious data are part of the product.
A reading that has not moved since Aug 13
The Blue below Dillon has reported exactly 53.9 cfs every day since Aug 13 (USGS). A steady reservoir release looks like this, and so does a stuck sensor, so confidence is reduced.
The river page note checks only about the last month of daily values, so it reports a run that started earlier as "for several weeks". Gauge height on the Blue has also held at 0.86 ft. Any run of 14 or more identical daily values adds this note to the river page and multiplies confidence by 0.85. The chart draws only what the agency reported; a missing day is left blank.
A gauge that is dark
The Piney sent no reading on Oct 2, so 10 of the 11 gauges in the feed reported that day. The card shows No data and tells anglers to check locally. It does not guess, and the Piney is not counted among the day's fishable waters.
A sensor that is missing
Gore Creek has no water temperature sensor, so the card leaves that stat out and shows Medium confidence. Without a temperature, a river cannot score above 6.9 or be the day's top river.
What a score does not do.
A score is a planning aid. It is honest about what it knows, and these are the things it does not know.
- It is not a guarantee. A good score does not promise a good day, and a low one does not rule one out. Conditions on the water can differ from the gauge.
- It does not see the fish. No catch reports go into a score, and hatch windows are published calendars, not sightings.
- It assumes the flow holds. Tomorrow and the weekend use that day's forecast with today's water carried forward. Reservoir releases can change without notice, so outlook confidence is always lower than today's.
- It reports what the gauges report. Agency data is provisional and can be hours old. Every card shows when its data was last updated.
- It does not replace the regulations. Check Colorado Parks and Wildlife for current fishing regulations and any closures before you go.
Put a score your customers can check on your own site.
Two plans, for any business. Both start with a free 30-day trial with no card needed, then run month to month, and you can cancel anytime by email. Both include the Scores v2 river card, with its "why this score" line and the weekend outlook. Lodging and rental hosts can show pass conditions alongside, or instead of, rivers.
The rivers and passes you choose on one website, with a small "via The Peak Colorado" credit.
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Card values, reasons and confidence come from the production Scores v2 data of Oct 2, 7:01 PM MT; the time on each card is when its gauge reading was taken. The Piney card has no reading, so it shows the feed time. The Red Cliff card is the card our site showed before Scores v2, from the update of Oct 2, 11:08 AM MT, the time it shows; its percentile comes from the Scores v2 preview run of Oct 2, 12:38 PM MT. Flow from USGS and Colorado Division of Water Resources gauges, weather from the National Weather Service, hatch windows from the published charts named above. CPW closure criteria: 2 CCR 406-1-104 F.1. Scores are a planning aid, not a safety service. Check Colorado Parks and Wildlife for fishing regulations and closures, and check cotrip.org or call 511 before you drive a pass.