Snake River, South Fork

GAGE LOCATION

DAY/YEAR
GRAPHS

CURRENT
STAGE/FLOW

WHAT TIME

Snake near Irwin

7 30 year

5.74 / 3050

12 am

Snake near Heise

7 30 year

1.88 / 3460

12 am

Snake at Lorenzo

7 30 year

3.59 / 2740

12 am

CITY

Swan Valley

NOAA

Accuweather

TWC

Idaho Falls

NOAA

Accuweather

TWC

HATCH

NYMPH/
LARVA

PUPA/
EMERGER

DUN/
ADULT

EGG-
LAYER

Spotted caddis

Green caddis

Golden stonefly

Salmonfly

Midge

Sculpin

Baitfish

The whole river is open, so anglers have lots of water to choose from. On warmer days you can look for hatching midges, and if you're tired of chucking big streamers, toss some tiny pupa and larva patterns, such as size 18-22 Brassies, Serendipities, Copper Johns, etc. On warmer days, you might see some blue-winged olives.

By late February, the big stonefly nymphs will start moving closer to the edges of the river, and there's always a few that lose their grip. That gets trout excited, so cast some size 6-8 Kaufmanns Stoneflies or similar big nymphs towards the end of February.

The upper part of the South Fork is in a deep valley, and cold air settles into it. Thus the river can be significantly colder than the nearby lower Henrys Fork. This makes trout lethargic and unaggressive, but you sure can catch a bunch of whitefish.

See the Rivers in General section for additional tips.