Fly fishing report · West

Lower Clark Fork River

A Lower Clark Fork report for anglers checking St. Regis flow, big-river access, trout and warmwater transitions, restrictions, and weather.

Check flow & weather

Today's river scoreHigh source confidence

Good

Best option: Bank / edge.

Bank and edge fishing remains a practical low-commitment option if access is legal and footing is safe.

Updated Jul 13, 11:17 PM UTCUsually refreshes about every 45 minutes

Recommended approachBank / edge

Mode scores adjust the river-wide score for the risks of wading, bank fishing, or floating.

WadeCheck

This report does not describe this as a primary mode. Verify legal access, depth, launches, and retreat options before planning around it.

Bank / edge · Best fit82/100

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.

River strategy

Confirm which lower reach you mean.

The lower Clark Fork changes from river reaches near St. Regis and Superior to dam and reservoir-influenced water farther downstream. This page uses St. Regis as the flow anchor and keeps the planning reach explicit.

Use the St. Regis gauge for the river reach, and do not apply it blindly to reservoir sections.
Expect a mix of trout, pike, bass, and reservoir influence depending on how far downstream you go.
Check FWP rules, current restrictions, and consumption guidance before harvest.
Large water, wind, and dams make boat and wading plans more serious than casual roadside fishing.

Why this score moved

HeatUse caution

The NWS forecast is near 94F. Fish early and verify water temperature where trout stress is possible.

FlowHelps score

USGS shows 6,310 cfs with a stable over about 6 hours trend. same-date USGS history (1930-2025, 96 readings) puts the normal middle range around 4,540 cfs-10,200 cfs. Flow is inside the same-date normal range, so weather, temperature, and access become the next checks.

SeasonHelps score

Early summer: Runoff drop and caddis or stonefly activity can improve river reaches.

Public alertsHelps score

No active NWS alert was returned for this forecast point.

Fishing usefulnessHelps score

Skip or pivot when the exact lower reach is unclear, FWP restrictions are active, wind makes the boat plan unsafe, water is too warm for trout handling, or public access and takeout details are not confirmed.

Read the water

What changes the plan.

Fish the lower Clark Fork when flow is stable, visibility is good, and you have a reach-specific access plan. If the river is high, hot, windy, or unclear, choose a colder tributary or a smaller reach.

Stable river flow

Fish seams, bars, side channels, and bank structure with nymphs, dries, or streamers.

High water

Avoid heavy wading and focus on protected banks only if safe.

Warm lower water

Check temperature and shift away from trout if handling would be stressful.

Reservoir influence

Treat slower sections as a different fishery with wind, boat, and species changes.

Field plan

Fish it with intention.

Best flows

Use RiverReports and USGS 12354500 at St. Regis for the river reach, and avoid applying that gauge blindly to reservoir-influenced water farther downstream. Stable visibility is the best trout window; warm or slow lower water can shift the target to warmwater species.

When to skip

Local plan

Start by deciding whether the day is a St. Regis river plan, a Superior-area float, or a lower dam-influenced trip. Then match flies, leaders, and species expectations to that exact reach.

Backup water

If the Lower Clark Fork is warm, windy, unclear, or too reservoir-influenced for the goal, compare the Blackfoot for colder freestone water, the main Clark Fork near Missoula for a more familiar town reach, or Rock Creek for a wade-focused trout plan.

Hatches & flies

Bring a flexible box.

TimingWhat to watchUseful flies

March to AprilSkwalas, March Browns, BWOs, midges, and early stonefly movementSkwala dry, rubberleg, March Brown, BWO emerger, zebra midge

Reviewed family · report says “Skwala dry”Skwala Stonefly PatternsSkwala is an insect and hatch label. Dark olive-brown nymphs and olive adult dries are materially different forms; seasonal timing also varies by watershed.See family guide

Reviewed family · report says “rubberleg”Stonefly Nymph PatternsStonefly nymph patterns generally emphasize two tails, a broad thorax, segmented abdomen, and bottom contact; rubber legs, biots, beads, and jig hooks define different exact forms.See family guide + 3 more reviewed guides in the Fly Box

May to JuneRunoff edges, salmonflies, golden stones, caddis, PMDsChubby Chernobyl, Pat's rubber legs, caddis pupa, PMD emerger, streamer

Reviewed pattern · report says “Chubby Chernobyl”Chubby ChernobylIdentify the construction, not the color: a long foam overbody over a segmented dubbed underside, rubber legs at two tie-in stations, two distinct buoyant synthetic-yarn wing sections, and a short flash tail. The paired wing stations and layered foam-and-dubbing body separate the reviewed Chubby from the original Chernobyl Ant and from generic foam hoppers or beetles.See photos & how to fish it

Reviewed pattern · report says “Pat's rubber legs”Pat's Rubber LegsA weighted long-shank nymph, variegated chenille body, two tails, and multiple pairs of long rubber legs identify the core form. Generic rubber-leg stoneflies remain a broader family, not automatic Pat's Rubber Legs matches.See photos & how to fish it + 3 more reviewed guides in the Fly Box

July to AugustHoppers, ants, beetles, nocturnal stones, spruce moths where presentHopper-dropper, foam ant, beetle, nocturnal stone, small perdigon

Reviewed family · report says “foam 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 + 2 more reviewed guides in the Fly Box

September to OctoberMahoganies, BWOs, October caddis, baitfish, fall streamer windowsMahogany, BWO, October caddis, sculpin, leech

Reviewed family · report says “Mahogany”Isonychia and Mahogany Dun PatternsIsonychia nymphs are active swimmers; emergers, parachute or other dry forms, and spinners occupy different levels. Mahogany Dun can be regional hatch wording, so it does not identify one exact fly recipe.See family guide

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 + 3 more reviewed guides in the Fly Box

Decide whether you are fishing a river reach or reservoir-influenced water before rigging.

Fish soft inside current, drop-offs, side channels, and bank seams on stable flows.

Use streamers for browns and pike in deeper or stained water.

On warm days, target smallmouth or pike instead of stressing trout in marginal temperatures.

If floating, account for wind, distance, takeouts, and dam-influenced water.

Access & responsibility

Know the entry. Know the exit.

Montana FWP regulations differ by Clark Fork reach and species. Check current rules, restrictions, and any advisory context before fishing or keeping fish.

St. Regis flow reach

Primary river-flow anchor for this Lower Clark Fork page.

Superior and Plains corridor

Large-river access and boat logistics become more important downstream.

Thompson Falls and reservoir sections

A different, dam-influenced plan with more warmwater and boat considerations.

Transparent sources

Check the facts behind the plan.

Last material review: 2026-05-31

flowRiverReports Clark Fork River at St. Regis flowUSGS Clark Fork at St. Regis 12354500 regulationMontana FWP fishing regulations accessMontana stream access law safetyMontana FWP current waterbody closures and restrictions safetyNational Weather Service forecast point

Common questions

Before you leave.

What should I check first before fishing the Lower Clark Fork River?+

Check the St. Regis gauge, exact reach, FWP restrictions, weather, access, and any harvest or consumption guidance.

Are there special regulations on the Lower Clark Fork River?+

Yes. Lower Clark Fork rules vary by reach and species, especially as the river transitions toward reservoir water.

What flies should I bring for the Lower Clark Fork River?+

Bring the hatch-chart flies, a few confidence nymphs, and a streamer box. Then adjust for water temperature, clarity, and the insects you actually see.

Can I wade the Lower Clark Fork River?+

Some edges are wadeable, but it is big water. Use official access and avoid assuming private banks are available.

When should I skip the Lower Clark Fork River?+

Skip it when flows are unsafe, temperatures stress trout, wildfire or emergency closures are active, or legal access for the reach is not clear.