Grand Canyon of the Colorado
Colorado River · Lees Ferry to Diamond Creek, Arizonagrand canyon to
866-284-5181 from your inReach and this reading
comes back over satellite. No app, no account, no cell service.
Which gauge people actually quote
Lees Ferry (USGS 09380000) is the number everyone means by "the flow." It sits just below Glen Canyon Dam at the launch ramp, so it reads the dam release rather than a natural river — which is why it rises and falls on a daily cycle with power demand instead of with weather. A reading taken at noon can differ by thousands of cfs from the same day at midnight, and that wave travels downstream with you.
Two more gauges matter once you are moving. Text either name the same
way you text grand canyon:
phantom— Phantom Ranch, river mile 87- USGS 09402500. Mid-canyon, and the one worth checking before the Inner Gorge. It also picks up the Little Colorado, so a brown spike here after a storm is the LCR, not the dam.
diamond— Diamond Creek, river mile 226- USGS 09404200. The takeout gauge, and the one that tells you what the last stretch and the shuttle road are doing.
Reading the number
Dam releases through a typical season run in the neighborhood of 8,000–16,000 cfs, with higher experimental flows some years. Low water is slower and more technical through the rock gardens; high water moves fast and washes out some holes while making others much worse. Neither end is a go or no-go on its own, which is the point of checking it against the trip you actually planned.
The gauge is information, not permission. It cannot see a flash flood coming out of a side canyon, what the wind is doing, or what your group can handle. Scout, and make the call on the water.
Permits
Private trips launch from Lees Ferry on a weighted lottery run by Grand Canyon National Park, with the main lottery drawn in February for the following year's launches. Commercial trips go through the park's concessioners. Confirm dates and rules with the park directly — this page tracks water, not paperwork.
Before you launch
Save 866-284-5181 to your phone and to your inReach while you still have signal, and send yourself a test message. Down in the canyon it is the difference between knowing the release and guessing at it. See how it works, or browse every run LateBoof knows.