Hazard Warning: Hazard information may be user-submitted and unverified. Conditions change frequently. Always scout rapids and obstacles yourself.

Rapid CA Class IV

Gray's Grindstone

Tuolumne - 4. Lumsden Campground (Merals Pool) to Wards Ferry Bridge (CA)

Monitor this Rapid

Gauge Conditions

Cherry Creek below Valley DAM near Hetch Hetchy CA Upstream Primary

Runnable: ? – ? CFS

Approximate - nearest available gauge. Use as general reference only.

Data from American Whitewater & USGS

CDEC Flow Data California

TUOLUMNE RIVER HTH Primary Dam Release

Elevation: 3,870 ft

TUOLUMNE RIVER FHH Primary

Elevation: 5,350 ft

TUOLUMNE RIVER EDT Primary

Elevation: 4,620 ft

Data from California Data Exchange Center (CDEC)

Description

This rapid is probably the most fun on the Tuolumne. It's about half a mile long full of rocks, holes, and waves. At lower water(below 1500 cfs), it's a zigzag between rocks and over drops. At about 2500 cfs, a big hole appears at the entrance on the right. You can skirt this hole by running a technical left route. At flows above 4000 cfs, this hole can easily flip rafts which would lead to a long swim.