Moab river levels, and what they mean.
The short answer
One number tells you most of what you need: the flow at the Colorado River near Cisco gauge, measured in cubic feet per second. It is published free by the United States Geological Survey, updated continuously, and it is the number your outfitter is watching too.
Roughly: under 3,000 the rivers here run low, clear and technical. Between 3,000 and 7,000 is the range most boaters consider ideal. Above about 9,000 the water gets pushy and less forgiving, and outfitters start raising minimum ages.
None of those numbers mean a trip is cancelled. They mean it is a different trip, and the good news is that the range that suits most guests is also the range these rivers spend most of the season in.
- Unit
- Cubic feet per second
- Key gauge
- Colorado near Cisco
- Low and technical
- Under 3,000
- Widely preferred
- 3,000 to 7,000
- Typical peak
- Around 20,000
What a cfs number actually is.
Cubic feet per second is the volume of water passing a fixed point every second. One cubic foot is roughly a basketball of water. So a river running at 5,000 cfs is moving about five thousand of those past you every second, which is why the number climbs into five figures and still sounds abstract.
The useful thing is not the absolute figure but where it sits relative to that river's normal range. On the Colorado near Moab, 4,000 is an ordinary autumn day. On a small creek, 4,000 would be a catastrophe. Always read the number as a position within the range, never on its own.
Two numbers you will see, and only one matters
Discharge is the cfs figure and it is the one to use. Gauge height is how deep the water is at the measuring station, in feet. Gauge height is easy to misread because a foot of rise means something completely different at every station, so ignore it and read discharge.
One more thing worth knowing: flow is not the same as speed. A high river is moving faster and carrying more water, which is why the consequences of a swim rise faster than the number suggests. That is the mechanism behind almost everything on the rest of this page.
The two gauges that matter here.
There are dozens of stations across the region and you need exactly two. Both are free, both update continuously, and both are what outfitters actually watch.
Colorado River near Cisco, Utah
Station 09180500. This is the reference gauge for Westwater Canyon, the Moab Daily and Fisher Towers. It sits below the Westwater run and above Moab, draining 24,100 square miles of the upper Colorado basin, so it reflects what the whole system is doing.
Green River at Green River, Utah
Station 09315000. The reference for Desolation Canyon and Labyrinth Canyon, and a useful check before a Cataract trip, since Cataract begins below the confluence and carries both rivers. Drainage here is 44,850 square miles.
How to read the page once you get there
Find the discharge figure, then look at the graph rather than the single number. A river at 6,000 and falling is a different proposition from a river at 6,000 and climbing hard, because the second one may be 9,000 by the time you launch. The shape of the last week tells you more than today's reading.
For a second opinion on what a given level means to boaters, American Whitewater's Westwater page carries flow notes and rapid descriptions contributed by people who run it, and the Bureau of Land Management publishes the canyon's own seasonal figures.
Westwater, flow by flow.
Westwater is where the numbers matter most, because it carries the hardest whitewater of any day trip here and because it changes character more than any other run in the region. The same named rapids behave completely differently across the season. The BLM puts the canyon's low water around 1,000 to 5,000 cubic feet per second and its typical peak near 20,000 in late May or early June.
| Flow | What the river is doing | As a booked guest |
|---|---|---|
| Under 3,000 | Low and bony. Rocks exposed, narrow lines, precise manoeuvring. Technical rather than easy | A puzzle solving day, and a longer one. Fewer big hits, more skill on display |
| 3,000 to 7,000 | The range most boaters consider ideal. Rapids are powerful and the lines through them are clear | The classic Westwater day. If you can pick your week, pick this |
| 7,000 to 9,000 | Building. Features get bigger, holes get stickier, the water starts pushing rather than flowing | Bigger and wetter. Still comfortably within normal commercial operations |
| 9,000 to 13,000 | Boaters call the teens unforgiving for a reason. Consequences of a mistake rise sharply, and the run gets noticeably faster | Expect higher minimum ages, more safety briefing and possibly a different boat |
| 13,000 to 20,000 | The least forgiving range on this river. Powerful, fast and continuous, and approaching the canyon's usual annual peak | Some outfitters restrict who they take. Ask specifically about your date |
| Above 20,000 | Above the typical peak, so an unusual year. Counterintuitively the discrete rapids begin washing out as everything drowns under volume | Fast, huge and strange. Fewer defined drops, far more water moving |
Skull Rapid, and the eddy below it
Skull is the one people ask about, and American Whitewater does not soften it: the rapid “has been the site of some epic mishaps.” Two features matter. Skull Hole is the flip risk in the rapid itself. Below it on river right is the Room of Doom, an eddy formed where a rock point pushes into the main current, with a recirculating flow that can stop a boat rejoining the river.
The threshold on the Room of Doom is lower than most write ups suggest. American Whitewater records that at flows above roughly 6,000 cfs parties have had to dismantle a raft and portage it up over the cliff to escape. That is inside the range many people describe as ideal, which is exactly why it belongs to your guide's judgement rather than yours. American Whitewater, Westwater Canyon
None of that is a reason to avoid the trip. It is the reason commercial Westwater runs carry experienced guides, helmets and a proper briefing, and why the BLM restricts the canyon to permitted operators. Your guide has run Skull a great many times and will tell you what today's version looks like.
What flow does to the other trips.
Not every trip is flow sensitive in the way Westwater is. For several of them the honest answer is that the number barely changes your day, which is useful to know if you cannot move your dates.
| Trip | Flow sensitivity | What actually changes |
|---|---|---|
| Moab Daily | Low | Runs across essentially the whole range. High water makes the small rapids splashier and the float faster. Class I to II either way |
| Fisher Towers | Low | Same. You came for the towers and they are there at every flow. Higher water shortens the float slightly |
| Labyrinth Canyon | Very low | Flatwater with no rapids at all. Flow affects how fast you drift and little else. Very low water can mean more paddling |
| Cataract Canyon | Very high | The Big Drops are only genuinely big at peak flow. By September Cataract is a milder river, with far more exposed beach for camping |
| Desolation Canyon | Moderate | Many small rapids that soften as the season drops. Higher flows also fill the side canyon waterfalls, which is a real reason to go early |
| Gates of Lodore | High | Hell's Half Mile and Disaster Falls change character considerably. Minimum ages rise at spring flows with some outfitters |
| Yampa River | Existential | Undammed, so there is no release to prop up the season. Its high use season ends in the second week of July for exactly this reason |
| Dolores River | Existential | Depends entirely on a reservoir release, which only happens when snowpack fills McPhee with enough to spare. Some years it does not run |
The practical read: if your dates are fixed and the forecast flow does not suit the trip you wanted, switching trip is usually easier than switching week. The trip comparison shows what else is running.
How flow moves through a year.
These rivers run on melted snow, so the year has a shape you can predict long before you can predict the weather.
Winter: the baseline
Low and stable. Snow is accumulating in the Rockies and the Uintas rather than melting, so the river runs on groundwater and reservoir releases. Almost nothing operates commercially.
Spring: the rise
April and May bring the climb as snow melts across a huge drainage. This is the fastest changing part of the year, and the reason a trip booked in March can look very different by the time you arrive. Flow can double inside a fortnight.
Peak: late May or early June
The high point, which the BLM puts near 20,000 cubic feet per second in Westwater in a normal year. How high it actually goes depends entirely on the winter snowpack: a heavy snow year gives a long powerful runoff, a poor one peaks early, briefly and lower. This is why people who care about big water watch snowpack reports in February.
Summer and autumn: the long decline
July onward the river drops steadily as the snow runs out. Rapids get more technical and less pushy, the water clears, and by September you are looking at a completely different river from the one in June. Monsoon storms can cause brief spikes but not a real rise.
The month by month guide works through what that curve means for each month, including crowds, heat and pricing.
What changes for you.
You are not choosing a line through Skull Rapid. Here is what the flow number actually alters about a trip you have booked.
The minimum age
The most common practical consequence. Several outfitters raise minimum ages during high water, because a smaller body is harder to recover from fast, cold water. If anyone is near a threshold, confirm against your dates. See rafting with children.
Whether you need a wetsuit
High water is snowmelt water and it is cold regardless of air temperature. Outfitters provide or hire wetsuits in spring. Take one when it is offered, even on a hot day. A swim in May is a genuine shock.
The boat you are in
Some outfitters move guests from paddle rafts to oar rigs or motorised boats at high flows, because the guide needs full control. If participating matters to you, ask what boat you will be in rather than assuming.
How long the day takes
Worth planning around. The BLM notes that high water trips through Westwater are faster, while low water trips at 1,000 to 5,000 cubic feet per second take considerably longer. An autumn trip can mean a longer day on the water for the same money.
How wet you get
The most reliable difference, and the one nobody warns you about. Spring flows mean bigger waves and a soaking on the small trips as well as the big ones. Low autumn water is a drier day with clearer water and better photographs.
Almost never whether it runs
Commercial trips operate across a wide flow range, and the BLM describes Westwater as challenging at all water levels rather than impassable at any. Lightning and wind cancel more days here than flow does. See the safety guide.
Three things people get wrong.
Higher is always scarier
Not quite. Rapids build to a point and then start washing out as volume drowns the features. Very high water is fast and serious but often has fewer defined drops than the middle range. The most demanding flows are usually somewhere in between.
Low water means an easy day
Low water means a technical day, and a longer one. Rocks are exposed, lines are narrow and precision matters more. The BLM's own description of Westwater is that it is challenging at all water levels. Many experienced boaters prefer it low.
The class rating covers it
A published class rating is a single label on a river that changes all season. American Whitewater rates Westwater III+, reaching Class IV at higher water, and outfitter websites rarely say which flow they mean. Ask what the river is doing your week.
Flow FAQs.
What does cfs mean in rafting?
Cubic feet per second, the volume of water passing a fixed point each second. One cubic foot is roughly a basketball of water. The figure only means something relative to that river's normal range, so read it as a position within the range rather than as a number on its own.
How do I check Moab river water levels before my trip?
Use the United States Geological Survey gauge for the Colorado River near Cisco, Utah, station 09180500, which covers Westwater, the Moab Daily and Fisher Towers. For Green River trips use the gauge at Green River, Utah, station 09315000. Both are free and update continuously. Look at the week long graph, not just today's figure.
What is a good flow for rafting Westwater Canyon?
Most boaters consider 3,000 to 7,000 cubic feet per second the sweet spot, where the rapids are powerful and the lines are clear. Below 3,000 the run gets technical, rocky and slower. Above about 9,000 it becomes considerably less forgiving. The BLM puts the canyon's typical annual peak near 20,000 in late May or early June.
Will my trip be cancelled if the water is too high?
Rarely. Commercial trips operate across a wide flow range and cancellations for water level happen only at genuine extremes. What is more likely is a raised minimum age, a different boat type or a longer safety briefing. Weather cancels more days here than water level does.
Is high water more dangerous than low water?
It carries different risk. High water is faster and colder, consequences of a swim rise sharply, and outfitters respond by raising age minimums and changing boats. Low water is technical rather than pushy, with exposed rocks and narrow lines. The BLM describes Westwater as challenging at all water levels, which is why guides plan for the specific level on the day rather than for a season.
What is the Room of Doom at Skull Rapid?
An eddy on river right below Skull Rapid, formed where a rock point pushes into the main current, with a recirculating flow that can stop a boat rejoining the river. American Whitewater records that above roughly 6,000 cubic feet per second parties have had to dismantle a raft and portage it up over the cliff to get out. It is a real hazard, and it is one of the reasons the canyon is restricted to experienced boaters and permitted commercial operators.
When is the water highest near Moab?
Late May or early June, at the peak of snowmelt out of the Rockies and the Uintas. The BLM puts Westwater's typical peak near 20,000 cubic feet per second. How high it actually goes depends on the winter snowpack, which is why a heavy snow year produces a long powerful runoff and a poor one peaks early and low. The month by month guide covers the whole curve.
What is the difference between discharge and gauge height?
Discharge is the cubic feet per second figure and is the one to use. Gauge height is water depth at the measuring station, in feet, and it is easy to misread because a foot of rise means something different at every station. Read discharge and ignore gauge height.
Does water level affect flatwater trips?
Barely. Labyrinth Canyon has no rapids at all, so flow mainly affects how fast you drift. Very low water can mean more paddling and slightly longer days. The scenery, the side canyons and the character of the trip are unchanged.
Checked the flow?
Now match it to a trip. The comparison shows difficulty, minimum age, drive time and typical price for all eight side by side.