Rivermatics

6 USGS Streamgages · Colorado River system

Blacks Fork flows and levels

Blacks Fork is gauged at 6 USGS streamgages in Utah and Wyoming, each tracked by Rivermatics. The mainstem runs about 190 miles (306 km) from headwaters to outlet. It drains into the Colorado River system. Drainage area at the gauges ranges from 126 square miles at Blacks Fork near Robertson, WY up to 2,981 at Blacks Fork near Little America, WY. The gauged reach falls about 2,675 feet, from 8,819 feet down to 6,144. Rivermatics issues a daily machine-learned 14-day flow outlook at 4 of them.

Gauges on this river, upstream to downstream

Ordered by drainage area, which is how far down the river each gauge sits. April and July figures are long-term median daily flows for that month from the USGS record — historical normals, not a forecast and not today's reading.

USGS streamgages on this river, ordered upstream to downstream
Gauge State Drainage sq mi Elevation ft April p50 cfs July p50 cfs Forecast
Blacks Fork near Robertson, WY UT 126 8,819 47.3 210.5 14-day
Blacks Fork near Millburne, WY WY 146 8,518 31.1 316.8 14-day
Blacks Fork below Little Blacks Fk at Fort Bridger, WY WY 259 6,628 — — —
Blacks Fork near Urie, WY WY 285 6,547 72.2 18.9 —
Blacks Fork above Smiths Fork, near Lyman, WY WY 324 6,435 26.2 32.3 14-day
Blacks Fork near Little America, WY WY 2,981 6,144 294.3 141 14-day

Typical flow by month at Blacks Fork near Little America, WY

The furthest-downstream gauge on this river, so the fullest flow it carries here. Long-term daily discharge percentiles from the USGS record (up to 64 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 10.1 43.9 131.2
February 22.8 80.1 214.7
March 69.5 211.6 723.4
April 89.9 294.3 1,039.3
May 71.1 629.5 1,947.1
June 55 640.6 2,174
July 23 141 752.8
August 1.9 48.1 232.4
September 1.7 34.9 195.6
October 11.5 55 223
November 18.6 62.2 229
December 17.4 45.9 150.7

All values in cubic feet per second (cfs).

Common questions

When does the Blacks Fork run highest?
June, on the long-term record at Blacks Fork near Little America, WY — the furthest-downstream gauge Rivermatics tracks on this river. Median daily flow there is about 640.6 cfs that month, against 34.9 cfs in September, the lowest. Upstream gauges peak on their own schedule; the table on this page gives April and July for each.
How many gauges are on the Blacks Fork?
Rivermatics tracks 6 USGS streamgages on the Blacks Fork, across Utah and Wyoming. Each has its own page with the site's full flow record and monthly normals. The river may carry other gauges that publish neither daily values nor discharge statistics; those are not tracked here.
Is there a flow forecast for the Blacks Fork?
Yes, at 4 of the 6 gauges. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on each basin's observed flows, weather and snowpack, and issues a daily outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on each gauge's live screen.
What river system is the Blacks Fork part of?
The Blacks Fork drains into the Colorado River system — it is a tributary somewhere in that chain, following the flowpath down to its terminal river. Rivermatics builds this from the USGS/geoconnex reference-mainstem network rather than from names.
Can I use Blacks Fork data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Other rivers in the Colorado River system

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