Tuolumne River

The Tuolumne is one of California's finest Class IV-V runs, featuring the legendary Clavey Falls—a mandatory Class V rapid with no portage option that serves as the literal and figurative gateway to the lower canyon. This is 18 miles of continuous technical whitewater through Sierra Nevada granite, with cold snowmelt water and consequences throughout.

If you're not comfortable at Class V, do not run this river. Clavey Falls is non-negotiable—you either run it or walk out miles of rough trail. This is a destination for experienced whitewater boaters, not a place to learn.

When to Go

April-May (1,500-3,500 cfs)

Peak runoff brings the highest flows and most powerful whitewater. Clavey Falls develops massive holes and exploding waves at high water. Grey's Grindstone becomes a long boulder garden with limited recovery pools. Water is numbingly cold (low 50s°F). This is expert territory—Class V becomes Class V+ at volume.

June (1,200-2,500 cfs)

Mid-season offers the sweet spot for most experienced paddlers. Clavey Falls is still serious but more manageable. Rapids remain continuous and technical without being overwhelming. Water temps rise slightly (mid-50s°F) but remain cold.

July (800-1,500 cfs)

Late season as snowmelt tapers. Clavey Falls becomes more technical with exposed rocks requiring precise lines. The entire run gets rockier and demands cleaner boat handling. By late July, most years the season ends.

When NOT to Go

Above 4,000 cfs: Clavey Falls becomes genuinely dangerous at high flows. The boat-eating hole at the bottom grows massive and has held swimmers and boats. Multiple rafts have flipped and wrapped at Clavey above 4,000 cfs. Unless you're extremely confident at high-volume Class V, wait for flows to moderate.

Below 800 cfs: The T becomes a rock-dodging nightmare. Clavey Falls in particular develops shallow rocks with tight technical moves. Grey's Grindstone requires constant maneuvering between boulders. The continuous nature of the river means you're grinding on rocks all day.

Late July onward: In most years, flows drop below runnable levels by late July. The season is genuinely short—typically 3-4 months at best.

Permit Strategy

Self-registration at Meral's Pool put-in. Fill out the form, drop it in the box, and go. While technically self-issue, USFS does limit group launches (check with Stanislaus National Forest ranger station for current policies). Success rate is around 90% with flexibility.

Permit Realities:

The Tuolumne's permit system is simple because the river self-selects. If you're qualified to run Class V whitewater, the permit is yours. If you're not qualified, no permit system will help you. The self-issue system works because only experienced boaters attempt the T.

Lumsden Road access can close: The dirt road to Meral's Pool is rough, unmaintained, and frequently closes after winter storms or during high fire danger. Call Stanislaus National Forest (209-965-3434) to verify road status before driving hours only to find it gated. High-clearance vehicles are mandatory—low-clearance cars will bottom out.

Special Considerations

• ⚠️ Clavey Falls is MANDATORY Class V with no portage - At mile 10 where the Clavey River enters, Clavey Falls is the crux of the run. This is a genuine Class V rapid with a massive hole at the bottom that has flipped rafts and held swimmers. There is no portage trail—the canyon walls are sheer. You either run Clavey or walk out miles of rough trail before reaching it. Scout from river-left. The line is typically far right to avoid the hole, but water levels change the optimal route. If you're not confident at Class V, do not put on this river.
• 🌊 Continuous Class IV-V means no easy sections - From put-in to takeout, the Tuolumne demands constant attention. Rock Garden, Sunderland's Chute, Grey's Grindstone, Clavey Falls, Hell's Kitchen, Pinball—the rapids are relentless. There are no long pool sections to rest and regroup. If you flip or swim, the next rapid is coming. This demands sustained focus and energy for the entire 18 miles.
• ❄️ Water is dangerously cold year-round - Sierra Nevada snowmelt keeps water temps in the 50s even in July. In April-May, it's in the 40s. A swim means immediate cold-water shock and rapid onset of hypothermia. Dress for immersion. Drysuits or thick wetsuits are mandatory for safety. Have dry clothes accessible at lunch/camps.
• 🪨 Grey's Grindstone is a long, technical Class IV - Before Clavey, Grey's Grindstone gives you a taste of what's coming. This is a half-mile boulder garden requiring constant maneuvering. Multiple lines exist, but all demand precision. It's called "Grindstone" for a reason—you're grinding through rocks continuously.
• 🚗 Lumsden Road is ROUGH and frequently closed - The 10-mile dirt road to Meral's Pool is infamous. Deep ruts, rocks, and washouts make it challenging even for high-clearance 4WD vehicles. After winter storms, sections wash out entirely. In summer, fire closures can shut access with no warning. Always call the Stanislaus NF ranger station (209-965-3434) before committing to the drive.
• 🏕️ Very limited overnight camping options - While the T can be run as an overnight trip, camping options are limited and require USFS approval. Most groups run it as a long day (8-12 hours put-in to takeout). If attempting overnight, contact Stanislaus National Forest in advance to identify legal camp locations.
• 📸 Pinball rapid tests boat control - After Clavey, you'd think the hard part is over. Pinball (mile 14) proves otherwise. This technical Class IV requires precise lines between boulders in a tight S-turn. At lower flows, the moves are delicate and unforgiving. Many groups have epic swims at Pinball after successfully running Clavey.
• 🚁 Emergency evacuation is difficult - The Tuolumne canyon is remote with steep walls and limited access. If someone gets seriously hurt, evacuation requires helicopter rescue or hiking out steep trails. Bring satellite communication (inReach or similar) and solid first aid capabilities. You're on your own for hours even if you call for help.
• 🔥 Wildfire season can close access entirely - The Stanislaus National Forest sees significant wildfire activity most summers. Roads can close with little notice, and smoke can make boating miserable. Monitor fire conditions before trips, especially July onward.