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Fly Fishing the Skwala Stonefly Hatch on the Big Hole River

Everyone knows the feeling, the itch to experience the first dry fly fishing of the year on Southwest Montana freestone rivers.  The first spring hatch, a.k.a. the best dry fly fishing of the year, is the Big Hole River Skwala hatch.

About the Skwala Stonefly on the Big Hole River

The Skwala stonefly makes it’s appearance as spring and the end of winter collide.  Fly fisherman come from across the country to catch the big browns.  On the Big Hole River this is around mid-April.  As the ice breaks free from the Big Hole and water warms to between 45-48 degrees for a consistent period of time, skwalas start to migrate to the banks of the Big Hole River to hatch.  The Skwala is a size #8-#10 stonefly with an olive colored body.  Like most stoneflies, Skwalas crawl onto rocky and brushy banks to hatch.  Unlike most stoneflies though Skwalas rarely fly in the air.  These stoneflies tend to crawl across the water when they lay their eggs.  Skwalas are hard to see in the water as they skitter with their wings closed on the surface.

Success Tactics for Fly Fishing the Skwala Hatch on the Big Hole River

Three tactics are helpful to know if you come to the Big Hole River to fish the  Skwala hatch.  1) What is the water temperature?  If it has been ranging in the 45-48 degrees for a period of several days, Skwalas could be hatching.  2) Have the fish been eating Skwala nymphs the past several days?  If so, adults are about to hatch.  3) If you walk the bank of the river and look at rocks, and willows do you see any stonefly shucks from hatched Skwalas or rising trout on the surface?  If you have, definitely fish the dry fly.

Since this is the first hatch of the year with a sizable meal on the Big Hole, trout tend to key into Skwalas pretty quickly.  These stoneflies are not in the same abundance on the Big Hole as Golden Stones or Salmonflies, but there are enough of them to make for some great fly fishing.  Dry fly fishing tends to be the best in the tail outs of the runs along undercut banks, pools, and ice shelves.

The lower third of the Big Hole River is where you will find the Skwalas.  Typically the river is still frozen in April above Jerry Creek.  You will find your best Skwala activity below the town of Melrose on the lower Big Hole River.  This is not an easy hatch to catch so make sure you are keeping your eye out for the signs.  This is a pre-runoff hatch, so it occurs when the Big Hole is warming up, but does not get so warm that snow starts to melt and blows out the river.

How to Time the Big Hole River Skwala Hatch

Timing of this hatch on the Big Hole is from April 1st-May 15th.  Spring is a time of change, so you have to monitor river flows, temperatures, and weather conditions to catch the elusive Skwala.  Experiencing a fly fishing vacation in Montana to catch this hatch is not to be missed.  This is a great time to experience trout feeding with fury, as they eat their first stoneflies of the season.  Other rivers in Montana that have Skwala hatches are the Bitterroot River and Clark Fork River in Western Montana.  Take note that in Western Montana the Bitterroot River Skwala hatch occurs about 3 weeks earlier than other Southwest Montana Skwala hatches due to the valley floor being lower in elevation.