Wade · Best fit82/100
Wading is in play only where your chosen access has clear footing, legal entry, and no forced crossings.
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Fly fishing report · West
Merced River
A Merced River report for Yosemite-to-Briceburg planning, reach-specific regulations, spring runoff safety, BLM access, hatch timing, and practical flies.
Check flow & weatherToday's river scoreHigh source confidence
82
Good
Best option: Wade.
Wading is in play only where your chosen access has clear footing, legal entry, and no forced crossings.
Updated Jul 13, 11:17 PM UTCUsually refreshes about every 45 minutes
Recommended approachWade
Mode scores adjust the river-wide score for the risks of wading, bank fishing, or floating.
Bank / edge82/100
Bank and edge fishing remains a practical low-commitment option if access is legal and footing is safe.
Float82/100
A float is in play where this report supports boat access and wind, releases, and shuttle logistics are manageable.
Confirm before you leave
Flow and weather right now.
Use the flow trend to confirm the score before you leave. Weather can change the safest and most productive fishing window.
Loading current flow and weather.
River strategy
Pick the reach before reading the hatch chart.
The Merced changes character from Yosemite headwater scenery to lower canyon and anadromous habitat. Regulations, access, and fish species change by reach, so this page treats the river as a planning system rather than one uniform trout stream.
- Use the Happy Isles or Pohono/Briceburg flow context for the reach you plan to fish.
- Check Yosemite rules separately from CDFW lower-river regulations.
- Spring runoff can make wading unsafe even when the weather is warm.
- BLM Briceburg-area access is useful, but roads, camping rules, and heat matter.
Why this score moved
Public alertUse caution
A heat alert is active near this forecast point, so the score is capped until water temperature and fish-handling risk are checked. NWS alert: Heat Advisory issued July 13 at 11:43AM PDT until July 16 at 11:00PM PDT by NWS Hanford CA.
FlowHelps score
USGS shows 133 cfs with a stable over about 6 hours trend. same-date USGS history (1916-2025, 110 readings) puts the normal middle range around 126 cfs-704 cfs. Flow is inside the same-date normal range, so weather, temperature, and access become the next checks.
SeasonHelps score
Early summer: Post-peak runoff can open useful trout and hatch windows, especially in cooler reaches.
Water temperatureHelps score
USGS water temperature is about 63F, with no heat stop triggered.
Fishing usefulnessHelps score
Skip the Merced during hard spring runoff, when Yosemite or Briceburg access is restricted, when canyon heat makes trout handling suspect, or when you have not sorted out whether park rules or lower-river regulations apply to your exact destination.
Read the water
What changes the plan.
The Merced is most useful when you match the day to the reach. In Yosemite, think access, park rules, and runoff. In the canyon, think flow, heat, BLM logistics, and CDFW's reach-specific regulation boundaries.
Low clear summer flow
Use stealth, long leaders, small dries, and shade-line presentations. Watch temperature.
Stable spring flow
Nymph edges, softer pockets, and side channels while staying out of dangerous main current.
High runoff
Skip wading. The river can be cold, powerful, and unforgiving during snowmelt.
Hot lower canyon
Fish early, carry water, and stop trout fishing if temperatures or handling conditions are poor.
Field plan
Fish it with intention.
Best flows
Use the upper-river trend as a warning system more than as a magic target. Once runoff begins to settle, pocket water and softer edges become worth the effort; when snowmelt is still pushing hard or the lower canyon is baking in heat, the best move is often to wait or switch rivers.
When to skip
Skip the Merced during hard spring runoff, when Yosemite or Briceburg access is restricted, when canyon heat makes trout handling suspect, or when you have not sorted out whether park rules or lower-river regulations apply to your exact destination.
Local plan
Choose Yosemite if you want cooler scenery-driven pocket water and can work within park rules, or choose the Briceburg corridor if you want BLM canyon access and accept the hotter, more exposed lower-canyon day. Fish one reach with purpose instead of driving the whole drainage in search of a generic Merced answer.
Backup water
If the Merced is too high, too hot, or too crowded, pivot to Hot Creek for a technical spring-creek day or to the San Joaquin if another reach-aware Sierra freestone plan fits the travel window better.
Hatches & flies
Bring a flexible box.
TimingWhat to watchUseful flies
SpringBWOs, March browns, caddis, stonefliesBWO emerger, March brown, caddis pupa, stonefly nymph
Reviewed family · report says “BWO emerger”Blue-Winged Olive PatternsBWO describes a hatch group, not one fly. Nymph, emerger, dry, cripple, and spinner profiles must stay separate because they occupy different parts of the water column.See family guide ↗
Reviewed family · report says “March brown”March Brown Dry FliesThis family includes traditional hackled, parachute, and Comparadun-style March Brown dries. Each exact construction rides differently and should be named when known.See family guide ↗+ 2 more reviewed guides in the Fly Box Early summerPMDs, caddis, yellow sallies, golden stonesPMD dry, elk hair caddis, stimulator, yellow sally nymph
Reviewed family · report says “PMD dry”Pale Morning Dun PatternsPMD names an insect group, not one fly. Pale nymphs, trailing-shuck emergers, upright or low-riding duns, cripples, and spent-wing spinners stay visibly separate.See family guide ↗
Reviewed pattern · report says “elk hair caddis”Elk Hair CaddisLook for a tented elk- or deer-hair wing, clipped hair head, dubbed body, rib, and hackle palmered along the body. The body color should be labeled because tiers often match different natural caddis colors.See photos & how to fish it ↗+ 2 more reviewed guides in the Fly Box SummerCaddis, terrestrials, small mayfliesAnt, beetle, caddis dry, parachute mayfly, small nymph
Reviewed family · report says “Ant”Ant PatternsAnt patterns can be foam, fur-bodied, winged, or sunken. The narrow waist and paired body lobes matter more than one material recipe.See family guide ↗
Reviewed family · report says “beetle”Beetle PatternsBeetle flies range from simple foam shells to hair-bodied and sunken forms. A rounded back and compact profile distinguish the family from ants and hoppers.See family guide ↗+ 3 more reviewed guides in the Fly Box FallBWOs, midges, October caddisBWO, zebra midge, October caddis, soft hackle
Reviewed family · report says “BWO”Blue-Winged Olive PatternsBWO describes a hatch group, not one fly. Nymph, emerger, dry, cripple, and spinner profiles must stay separate because they occupy different parts of the water column.See family guide ↗
Reviewed pattern · report says “zebra midge”Zebra MidgeLook for a very slim tapered thread body, evenly spaced contrasting wire rib, a small bead, and no tail or wing. The reviewed classic is black with silver wire and a silver bead. Red, olive, brown, glass-bead, jig-hook, resin-coated, or tailed forms must remain labeled variations rather than replacing the classic identity.See photos & how to fish it ↗+ 2 more reviewed guides in the Fly Box 01
Choose Yosemite, Briceburg/canyon, or lower-river habitat before applying any rule summary.
02
Use the nearest relevant gauge instead of reading one flow number for the whole river.
03
During runoff, fish from the bank and avoid crossings.
04
Look for trout in soft edges, plunge-pool lips, and shaded pocket water.
05
Carry extra water and sun protection in the canyon.
Access & responsibility
Know the entry. Know the exit.
Verify CDFW reach-specific Merced River regulations and Yosemite National Park fishing rules before fishing. Rules differ by dam, bridge, park, and lower-river boundary.
Yosemite Valley and Happy Isles context
Park rules, seasonal access, and runoff conditions matter. Check NPS before fishing.
Pohono Bridge and lower Yosemite context
Useful for flow and park-reach planning, especially during runoff.
Briceburg and BLM canyon access
A major public planning area with campgrounds, road conditions, trails, and heat exposure.
Lower Merced anadromous reaches
Rules can be very different from Yosemite trout water. Use CDFW reach boundaries.
Transparent sources
Check the facts behind the plan.
Last material review: 2026-05-31
flowRiverReports: Merced River at Happy Isles BridgeflowUSGS monitoring location: Merced River at Happy Isles BridgeflowNPS Yosemite hydrology dataaccessBLM Merced River Recreation Management AreabackgroundCDFW Merced River drought and steelhead case studyregulationCDFW Title 14 and regulation noticessafetyNational Weather Service forecast point near Merced River canyon
Common questions
Before you leave.
What Merced River reach is best for fly fishing?+
It depends on season and rules. Yosemite and Briceburg/canyon reaches are the main trout-planning anchors, while lower reaches have different anadromous regulations.
What gauge should I check?+
Use Happy Isles, Pohono, or other Merced gauges that match your reach. This page displays the RiverReports Happy Isles gauge for upper-river context.
Is spring runoff dangerous?+
Yes. The Merced can be cold, fast, and unsafe to wade during runoff even on warm days.
Can I use the same rules in Yosemite and below the park?+
No. Check Yosemite National Park rules and CDFW reach-specific rules separately.