Yellowstone Park, July 11th, 2023

Mountain Ash Creek; the least visited of Fall River Basin Streams

Fall River Basin in the southwest corner of the park currently offers the best fly fishing in our area. In saying that, we are looking at the big picture where tranquility, great scenery, and superb fishing reign supreme. The major streams here include Bechler and Fall Rivers and Boundary, Mountain Ash and Proposition Creeks. The still waters are Beula and Hering Lakes. For this report, let’s look at the streams. We will look at the lakes in the next report.

Each of these streams is not influenced significantly by man-made development, except for a minor inflow from Grassy Lake Reservoir to Fall River. Currently each is at natural flow; clear, cool and hosting a great population of cutthroat and cutt-bow hybrid trout. No whitefish or suckers are present! Float fishing is prohibited: wading only! There are no introduced brookies in Bechler River and Boundary Creeks where the other streams host them.

Currently top water is approaching its best (until terrestrial insects form in huge populations). The hatches going on now include diminishing sallies, numerous PMDs, caddis, and an excellent evening brown drake hatch. In good water years, like this year, there is a good green drake hatch that begins each day in mid-July during afternoons when water temperatures get into the low 50s in Deg. F. Six weight rods, floating lines and long leaders are best. So is stealth, so minimize bank side appearances.

If there are any disadvantages to visiting these streams. it is at least the three mile walk through bear country and the need for DEET to ward off insect pests. For the Bechler River-Boundary Creek side Bechler Ranger Station is the jump-off point. The station is fully staffed 24/7, sells park licenses, has horse party facilities, and solid information about trail conditions. For the Fall River side, access is from the Ashton-Flagg Road. Primitive, but passable roads give closer access to the other streams. We, at the shop can identify these for you and we can provide further information for all waters.

We will keep up and report on fishing conditions in Fall River Basin throughout the season simple because it is such a special place in this area.