Friday, January 18, 2013

To Catch BIG fish -- Part II -- A Blue Mountains Fly Hatch Chart


This is a guide to the major aquatic insect hatches for streams of the Blue Mountains of southeast Washington and northeast Oregon, primarily the trout bearing streams of the area. The guide was developed in the years 2000-2001 at the time when Dr. Newell was an environmental biologist at the Hanford Nuclear Station in Washington, and Mr. McKain owned a fly shop in Pendleton, OR. Detailed hatch information is provided for mayflies, stoneflies and caddisflies. Other insect groups and fly selections are mentioned at the end of the guide.

The guide contains names of common insects, emergence=flight periods and recommended fly patterns. This chart was developed from several years of collecting by the authors to help fly fishermen ‘match the hatch’ of aquatic insects to help them catch trout.

The streams of the study area flow out of the Umatilla National Forest, and the Wallowa-Whitman National Forest usually from heavily timbered, narrow steep canyons. Eventually they flow out of the Forest eventually entering wider valleys containing agricultural activities and homes. After they enter these wider valleys the usual result is less gradient, warmer temperatures, increased nutrients and sediment. For example the Touchet River drops in elevation from 3300’ near the Bluewood ski area to 1613’ at Dayton, a 20-mile distance, and 450’ elevation at its confluence with the Walla Walla River. At some point downstream some of these streams no longer hold trout and concurrently the insect fauna is influenced by these water quality changes. Some streams change less (Tucannon River, Looking Glass Creek) than others (Touchet River, Mill Creek, Walla Walla River). It is difficult to pinpoint where trout-bearing water begins and ends and is not really important for this work. The geographic area covered by this chart is; bounded on the south by the John Day River, on the north and east by the Snake and Columbia rivers, and Oregon Hwy. 207 on the west.

 This chart was developed from several years of collections of insects by the authors to help fly fishermen match the hatch. Our largest source of public prestine trout waters are in the Umatilla and Wallowa-Whitman National Forests of northeast Oregon, where many days you can spend fishing with no one in sight but the wildlife around you. When fishing for trout in this area, it is not uncommon to experience a 200+ fish hookup day. Keep in mind... while having a trout or steelhead hooking up to a dry fly, is a lot of fun; 90% of a trout's diet is sub-surface insects, plant particles, sticks and stones.

Development of hatch charts in mountainous areas of the western U.S. is difficult due to many factors that can influence hatching times. One species may hatch weeks apart in different streams, different parts of the same stream and some species have multiple generations per year in one area and single generations in others. A hatch will normally begin at lower elevations and hatches of the same insect will occur days later at higher elevations. Hatch densities can vary from year-to-year. Some insects will inhabit only the upstream portions of a stream and others are found throughout the stream system.

We have selected insects that are the most abundant and widespread throughout the region and throughout trout water of individual streams. Other insects may be abundant in isolated streams or portions of streams. If you are prepared to match the hatch with the patterns listed here you will be ready for most major hatches throughout the fishing season. If you have comments, suggestions, or data (e.g. specimens) that will increase the accuracy of this chart, contact either author.
For more fly patterns, contact your local fly-fishing shop or one of the many excellent books on fly fishing the west. For photographs of these insects and more workable fly patterns, use one of the many published hatch guides written for western streams or consult such reference books as;  Hatch Guide For Western Streams, Mayflies, Caddis, the Super Hatches, Caddisfly,  Trout Flies, Hatches II, or Fish Food, to name a few available sources.

The book Western Mayfly Hatches may be the single best source of information on western Mayflies. Also see the excellent web site, We have listed some of the major insect hatches by their Latin generic and species names. We did this to help interested fishermen to search out additional information of a particular hatch, including photographs, from other publications or the internet, design their own patterns based on the photos, and associate common fly names with scientific names. Common names are notoriously inconsistent, while Latin names are very consistent.

In addition to hatches, we have listed some “non-hatches”, and terrestrial insects.  These non-hatches are not insects and therefore do not have adult phases that leave the water. As you use this chart, don’t forget about the nymphs of this insects, emergers, stillborn duns, and pupae when appropriate. Stonefly nymphs crawl out of the water to hatch so the presence of cast skins is good evidence of a recent hatch. This chart is organized by months. For a particular hatch you will usually see the genus/species of aquatic insect, an appropriate dry fly, nymph pattern, and suggested size. Some genera listed here represent several species, each species may call for a different pattern, e.g. for the species of the mayfly Cinygmula, we list the red quill, light cahill, pale brown dun, and pink lady to cover all of the species.
There are interesting differences between streams in this area and other western trout streams. 
The giant stonefly/salmonfly (Pteronarcys) hatches/emerges much earlier in this area.

Click on this link to identify - more Stoneflies

The medium stonefly, Skwala, has no common name and is very abundant, with hatches in March and April. The term “hatch” is very generic and probably refers to when an aquatic insect leaves the water and becomes an adult (mayflies) and for others the adult may be around long after it emerged (caddisflies and stoneflies). The Blue Mountain streams can have diverse assemblages of insects. On the Touchet River alone we have collected 30 species of mayflies, 35 species of caddis and 35 of stoneflies.

Hatches of the western green drake are small and scattered in our Blue Mountains Ecoregion.     
Click on this link to identify - more Mayflies.

If we had to recommend one fly to match in this region of the west, it would be the spotted sedge, imitating the adult of the caddisfly family Hydropsychidae, including Hydropsyche, and smaller Cheumatopsyche, which are the most common insects in Blue Mountain Streams. One or more species of these caddis species are present for most of the fishing season. These caddis genera definitely have a "super hatch."  If you fish below western dams these caddisflies can reach incredible numbers. Both of these caddisfly genera can occur in stream sections not containing trout.
Click on this link to identify - more Caddisflies.

The longest emergence/flight period and most spectacular insect of this area is the October caddis, Dicosmoecus gilvipes.
Adults can be seen from mid-September until early November. A drive up the Touchet River on any autumn evening one will see hundreds of adults of this, the largest caddisfly in the study area.

How does one use this hatch guide? One way to use these data is to find a pattern book and tie the flies recommended in this guide. If you want to know more, find a hatch guide that contains photographs and recommended patterns. Many such guides have been published, such as Hatch Guide For Western Streams, Hatch Guide to the Deschutes River, Hatch Guide to Lakes and there are several others. Further afield there are guides for Yellowstone Park, Snake River, Bighorn River, etc. Some of the insects found in the study area are known from other western streams. A little research on the internet will yield scores of data sources. For mayflies we recommend Western Mayfly Hatches by Hafele and Hughes. With this one book you will have all of the information you need about mayflies in the west. There are no books like this one on mayflies for stoneflies or caddisflies although Caddis, the Super Hatches is a good, little known book. On the internet see the web sites like; ~~~ /watch?v=k_GZeKZ-HL8  ~~~  for many insect photographs, common names and information of interest to the fisherman.


Most of our high mountain lakes are not accessible until April, and some lakes above 8000' it maybe as late as July 4th before you can hike into them. It always seems the trout are waiting for the first fly of the season to hit the water, and then the lake will churn right before you eyes. The lakes and ponds that can be reached in March and April can be best fished with Chironomids (16-20), Pheasant Tail Nymphs (18-22), Red San Juan Worm (12-14), and Midge Pupae (18-22) patterns. We have found the best flies to use in our stillwaters for trout beginning in May, are wooly buggers Elk Horn Lake Special (14) on overcast or sunny days, Blue Mountain Dragon (8) on sunny days, and a Rickards' AP Emerger (12-16) in the early am and late pm hours.

Orange, black or brown leech patterns Wooly Bugger (6-14) work well almost anytime in stillwater. Good dry flies to use in our Blue Mountain lakes are Adams (14-22), Cream or Dun Callibaetis (10-16), Baetis/ BlueWinged Olive (10-14), Comparadun Gray/Sulphur (14-18) P.M.D, Trico Spinner (14-22). Many lakes hold crayfish in the 2"- 4" range, most in a green to amber coloration.

We have listed all genera and species names in italics.


Winters are mild at lower elevations of the Blue Mountains and spring comes early, while the snow can impede fisherman movement at higher elevations. Runoff is usually greatest in late winter as rains cause snowmelt and high, turbid streams. While Rocky Mountain streams may be high into July, Blue Mountain streams are dropping in May. There are prolific hatches in the late winter. The popular salmonfly begins hatching much earlier in this region than elsewhere in the west. Small black winter stoneflies can be seen crawling along snow banks at higher elevations (Capnia, Nemoura). The following specific insects can be expected as adults at lower elevations; midges, mayflies like Baetis, Rhithrogena, and stoneflies like Pteronarcys, Skwala, and small winter stoneflies.

DRY:   Baetis-Blue winged olive and blue duns (18-20);
Rhithrogena-Western March browns, hairwings, CDC, or comparaduns (10-14); Skwala stonefly, stimulator (light olive) ( 8-10, 2XL  ); Pteronarcys-Salmonfly or giant stonefly, sofa pillow, stimulator, Clark's stonefly ( 4-8, 3XL); Small black winter stonefly (Capnia, Isocapnia, Nemouridae), small brown stone ( 12-16).

NYMPHS: Krystal flash nymph, Baetis nymph, pheasant tail (14-20, 2XL); Gold ribbed hare's ear, March brown soft hackle, CDC emerger (10-14); Skwala; small golden stone (8-10 2xl); Kaufmann's black stone, black stone, Box Canyon stone (4-8, 3XL); Hare's ear, pheasant tail (12-16), prince nymph (10-14).


Streams can be high and dirty in April, some streams are closed to fishing and, dry fly fishing can be impossible. The weather will dictate the actual stream/fishing conditions. Warm weather and/or rain will turn most streams high and muddy. Some of the caddisfly (Brachycentrus=mother’s day caddis), stoneflies (Skwala, Pteronarcys, Hesperoperla), and a few mayfly (Rhithrogena-Western March brown) hatches can be heavy, but timing is critical to see the heaviest hatches.

DRY:  Rhithrogena-Western March Browns, CDC, or comparaduns (10-14); Brachycentrus-black caddis, Mother’s Day caddis, American grannon, deer hair caddis  (12-16); Skwala  stonefly, stimulator (light olive) (8-10, 2XL); Hesperoperla, Golden stones, orange stimulator, madam X (6-8 2XL ); Pteronarcys, Salmonfly or giant stonefly, sofa pillow, stimulator, Clark's stonefly (4-8 3XL ).

NYMPHS: Gold ribbed hare's ear, March brown soft hackle (10-14); Brachycentrus larvae, herl nymph (10-16 2XL); 3-Kaufmann's stonefly (4-8 3XL), prince nymph (10-14), little brown stone, golden stone nymph (10-6 2XL).
See March for other early spring patterns to use. 


By May the runoff is waning in most Blue Mountain streams. Large streams and rivers like the Umatilla River, and Grande Rhonde River, John Day River, Powder River, Wallowa and Minam Rivers may still be high and dirty however. By the end of May hot weather is close at hand and the majority of hatches will be happening as days are longer and the water warms. Some of the species seen in April are still hatching along with some other caddis (Cheumatopsyche), and stoneflies (Pteronarcella) in May. Pteronarcella is the smaller identical cousin of the giant stonefly.

DRY: Rhithrogena, Western March Browns (10-14); Brachycentrus, black caddis (12-16); Cheumatopsyche, elk hair caddis (12-18); 3-Skwala stonefly, stimulator (olive, yellow color) (8-10 2XL); Pteronarcella, small salmonfly, orange stimulator (8-10 2XL); Hesperoperla & Calineuria-Golden stones (6-8 2XL).

NYMPH: Hare's ear (10-14); herl nymph, Martinez nymph (10-16 2XL); bead head caddis, sparkle pupae (12-16); Skwala, small golden stone (8-10 2XL), Kaufmann's stonefly (8-10 2XL), golden stone nymph (6-10 2XL).


By June the weather can be hot at low elevations, the streams have dropped and cleared and the mayfly hatches are beginning in earnest. We have seen simultaneous hatches in early June of several kinds of mayflies (e.g. Acentrella, Baetis, Drunella, Ephemerella, Paraleptophlebia, Rhithrogena and Epeorus), caddisflies seen in earlier months, and some stoneflies. Matching the hatch can be easy or hard during these conditions. Multiple hatches are common.

DRY:  Baetis, blue dun (18-20); Cinygmula, red quill, light cahill, pale brown dun, pink lady, parachute dun, comparadun (12-16); Drunella doddsi and grandis, western green drakes (8-10);  flavilinea, flavs. lesser green drake, blue-winged olive (14-16 );  E. infrequens/E. inermis, pale morning duns, (14-16 ); Paraleptophlebia, mahogany duns, blue quill (12-16 ); Epeorus, Quill Gordon, cahill (10-16); Rhithrogena, Western March brown (a few stragglers only), (10-14 );  Cheumatopsyche, caddis, elk hair caddis (12-18); Hydropsyche,  spotted sedge-a "super hatch", elk hair caddis (10-14 );  Skwala stonefly, end of this hatch, stimulator ( 8-10 2XL); Hesperoperla & Calineuria, Golden stones, end of this hatch, stimulator (6-8 2XL); Pteronarcella, small salmonfly, black stimulator ( 8-10 2XL ), Glossosoma little black short-horned sedge.

NYMPH:  Krystal flash nymph, Baetis nymph, pheasant tail, brown nymph, bird's nest (12-20, 2XL), olive hare's ear (8-10 2XL); bead head caddis, sparkle pupae (10-16), Kaufmann's golden stone (6-8 3XL), black stone nymph (8-10 2XL), see previous months for previously listed organisms


By July the weather is getting very hot, the streams are flowing much lower, slower, the water is warm, and the hatches are generally in late mornings through evenings. The hatches are very similar to those seen in June with the addition of the small yellow, tan, green, or orange summer stoneflies (Chloroperlidae=Alloperla, Suwallia or Sweltsa). Adults of the caddisflies Hydropsyche and Cheumatopsyche are present all summer long.

DRY: Baetis-Blue-winged olive, blue duns, blue-winged olive spinner (18-20); Cinygmula, red quill, (other patterns see above)(12-16); D. grandis and D. doddsii, Western green drake, (small hatches) (8-10);
D. flavilinea
, flavs. lesser green drakes, blue-winged olive (14-16 ); E. infrequens/E. inermis, pale morning duns ( 14-16); Paraleptophlebia, blue quill, mahogany duns (see above for other patterns)( 12-16); Epeorus, Quill Gordon, cahill, (10-16 ); Brachycentrus, black caddis and a "superhatch" (12-16 ); Cheumatopsyche caddis, elk hair caddis (12-18 ); Hydropsyche, spotted sedge and a "superhatch", elk hair caddis ( 10-14 ); Chloroperlidae-yellow sally stoneflies (10-16 2XL).

NYMPHS: Krystal flash nymph, Baetis nymph, pheasant tail, bird's nest, bead head nymphs- hare's ear, (14-20, 2XL), olive hare's ear (8-10 2XL), bead head caddis, sparkle pupae (10-16), little yellow stone (10-14 2XL), prince nymph (10-14)


This month has the dog days of summer. The days can be extremely hot and the evenings warm. The streams are very low and warm. The hatches will be early and late in the day, primarily mayflies, with some caddis and a few summer stoneflies, similar to what is listed for July. Shady, cool canyons could see some mid-day hatches. Best fishing results seems to be late afternoon when shadows appear over gin clear waters.

DRY:  Cinygmula, Quill Gordon (10-16); E. doddsi and E. grandis, small hatches, western green drake (8-10); D. flavilinea, flavs, lesser green drakes (14-16 ); E. infrequens/E. inermis, pale morning duns (14-16); Paraleptophlebia, blue quill, mahogany duns(see other patterns above) (12-16); Epeorus, Quill Gordon, cahill (10-16); Brachycentrus, black caddis (12-16); Hydropsyche, spotted sedge, elk hair caddis (10-14 ).

NYMPHS: Pheasant tail, dark hare's ear, bead head, bird's nest (14-20 2XL), olive hare's ear (8-10 2XL), bead head caddis, sparkle pupae (10-14 2XL), prince nymph (10-14), October Caddis (4 2XL), see previous months for other patterns.


The very hot weather is over but the days will still be very warm and bright. Most of the major mayfly hatches start to wane in September. A few leaves will be starting to turn color and the streams will be very low unless some fall rains have occurred. As the days and nights cool, hatches will occur mid-day again. Toward the end of the month, in cool shaded canyons and at higher elevations the mornings and evenings are too cold for insects to fly and mid-day will provide the only hatches. Fewer hatches will occur as the month proceeds including the appearance of the largest caddis in the area, Dicosmoecus and a close, smaller relative, Onocosmoecus. Fishing can be spectacular however.

October Caddis imitation
DRY:  Baetis, blue wing olives and duns (18-20); D. doddsi and D. grandis, small scattered hatches (8-10 ); E. infrequens/E. inermis, pale morning duns ( 14-16); Paraleptophlebia, mahogany duns (12-16); Brachycentrus, black caddis (12-16 ); Hydropsyche, spotted sedge, elk hair caddis (10-14 ); Dicosmoecus, October caddis or giant orange sedge (6-8 2XL); Claassenia, fall stonefly, we are calling it the cream stonefly, orange and yellow hopper patters, yellow stimulator ( 6-8 2XL).

NYMPHS: Hare's ear, pheasant tail (10-14), olive hare's ear (8-10 2XL), buckskin larvae, stone cased caddis (6-10 3XL), golden stone nymph (6-10 2XL), prince nymph (10-14), see previous months for other patterns...

October Caddis and a #10 Stimulator


Fall is in the air. Toward the end of the month, frost is possible and perhaps an early dusting of high elevation snow can occasionally be seen. The nights are longer and colder. Fall rains can dirty the water and knock leaves into the water making nymph fishing difficult. The stream water is cold and a few sporadic hatches will occur for a few hours during the warmest part of the day or sunniest reaches of streams. Some fishing seasons close at the end of this month. With the possible exception of the October caddis hatches, none will be spectacular, except for the mayfly Paraleptophlebia bicornuta that emerges later than any mayfly we have seen. . Occasionally one is surprised on isolated stretches of streams when a large caddis (Neophylax) hatch occurs (tributaries of the Walla Walla and Touchet Rivers).

DRY: Neophylax, brown dot sedge, dark speckled sedge, dark elk hare caddis (8-10 2XL), Dicosmoecus, October caddis or giant orange sedge, orange stimulator, orange hopper patterns (6-8 2XL);  Paraleptophlebia bicornuta, probably the last mayfly hatch of the year, a tough customer, blue quill (12-14); Onocosmoecus unicolor, great late summer sedge (10-12), a tough customer but never very abundant.

NYMPH: bead head caddis, dark hare's ear (8-10 2XL), buckskin caddis, stone cased caddis (6-10 3XL), golden stone (6-8 2XL).


Most stream are closed to trout fishing on November 1st in the Blue Mountain Region. Please check your Oregon and Washington fishing regulations before grabbing your rod, reel and hitting the road. This is the wettest month of the year. Snow is probable in the upper reaches of streams early and probable in all areas by late month. Hatches during the cold days of November are rare as freezing nights are possible. A few stragglers of the October caddis may persist if the nights have not been excessively cold.. Midge hatches can be expected (although many are very small) during the milder days and it is too early for the tiny black winter stoneflies. Midge (or chironomid) pupae patterns would be a good choice also. There may be some large, rare caddisflies that are usually not numerous (Psychoglypha). An occasional blue dun may be seen on a sunny day. Nymphs are probably your best bet.
Between November 1st and April 15th, most anglers turn the attention to Pacific Northwest steelhead fishing. Prehaps the best all around fly to use during this time is an articulated Egg-Sucking Leech (sizes 2-6).

This is not a good time for dry flies. This is the coldest month of the year. Occasionally, quiet, sunny winter days will provide some short hatches of midges or an occasional blue dun. A few tiny black winter stoneflies can often be seen on the snow. The water is very cold and the fish are inactive. Winter rains can turn most streams turbid. Nymphs are the best choice. One might do better tying flies for next season or chase steelhead.

Some other rivers in the Upper Columbia River Basin that we fish steelhead, usually in the forth quarter of the year.

Flies – size #2 hook
Gen. Location
Sept – Nov
Nez Perce Indian Reservation
Oct – Nov
Egg Sucking Leech
Ringold area
Sept - Oct
through The Canyon
Grande Ronde (WA)
Oct – Nov

Dec - Jan
Green Butt Skunk,
Muddler Minnow, Leeches (in winter)
Boggan’s to Shumaker
Stateline / Big Bend area
Lower Walla Walla

Upper Walla Walla
Sept – Dec


Dec - March
Kaufmann / other's fly patterns


egg patterns
below Stateline Rd
above Stateline Rd
Lower Touchet

Upper Touchet

Jan - March

red and orange egg pattern w/skein

Lamar to Lukenbill Rd -------------------

Upstream of
Lewis and Clark Park
Grande Ronde (OR)
late Oct

Nov - Jan
Dry flies
OR-WA stateline to Troy

OTHER INSECT GROUPS for trout fishing

  1. Diptera, Chironomidae=midges are common in all streams and hatches can occur about any time. Most adults are very small; Ceratopogonidae=biting midges.
  2. Diptera, Tipulidae=crane flies
  3. Diptera, Simuliidae=black flies
  4. Coleoptera; riffle beetles, water pennies
  5. Lepidoptera; aquatic moths
  6. Odonata; damselflies


Several insects that do not live in water, can offer great summer fishing opportunities. You should always have a few patters to imitate the following terrestrials:
1.       Ants (probably the most abundant terrestrial insect, especially in forested areas.)
2.       Beetles, black
3.       Caterpillars, moths, butterflies
4.       Grasshoppers-many grasshopper patterns could be taken by fish as caddis or stonefly adults.


Consider carrying and fishing patterns for the following critters that do not hatch or are not insects:
1.       Crayfish-crayfish are common in most streams of the reference area. These brownish orange creatures can get up to two inches long in the fall.
2.       Leeches
3.       Snails
4.       Scuds or often erroneously called "freshwater shrimp"
5.       Minnows, sculpins, eggs (salmon or steelhead), or small trout.
6.       Worms-all the local streams contain small aquatic worms up to 1 inch long that look much like common earthworms found in your garden.
7.       Tailed frog (Ascaphus montanus) has a larvae about 3” long and black
8.       Salmon/steelhead eggs and flesh from decaying salmon carcasses.
9.       Arachnids=water mites

This writer would also like to make reference to the other articles posted to this blog as an aid to catch BIG fish: 
~ To Catch BIG fish -- Part 1 -- Gearing up, hooking, chasing and landing big fish

~ To Catch BIG fish -- Part III -- Where to go and when

UPDATED: by Dale McKain - January 2013

Tight lines and good fishing.

Walla² Fly Fishers