South Boulder Creek – 05/04/2025

Time: 11:15AM – 3:00PM

Location: Below Gross Reservoir

South Boulder Creek 05/04/2025 Photo Album

I normally avoid fly fishing on weekends, but on Sunday, May 4, 2025 I made an exception. The weather forecast for Monday through Wednesday of the upcoming week portended adverse fishing conditions, so I made the trip to South Boulder Creek. I kept my eye on the flows below Gross Reservoir, and they remained steady at 45 CFS for more than a week. These flows are a bit low for my preference; however, I have enjoyed success at even lower levels. The high temperature in the canyon was forecast to reach the mid-sixties, so that also played into my decision.

By the time I made the relatively short drive and jumped into my gear and hiked to the creek, my watch displayed 11:15AM. My trip through Flagstaff Mountain Park was slowed by a caravan of cyclists climbing the steep and winding road. Kudos to all the riders who finished the ascent.

Covered in Spots

The parking lot at the Walker Ranch Loop Trailhead was nearly full, but I lucked out and found a recently vacated slot. I wore my fleece hoodie, but I avoided my long sleeve undershirt and stuffed my raincoat in my backpack. The temperature at the parking lot was 61 degrees. I have been using Pinecliffe, CO in Weather Underground as my proxy for weather at South Boulder Creek, but I concluded that the higher elevation mountain village probably understates the air temperatures in South Boulder Creek below Gross Reservoir.

Narrow Ribbon of Fishable Water

To begin my quest for trout I began with a peacock size 14 hippie stomper and then added an olive perdigon on a three foot dropper. Beneath the perdigon I knotted a size 20 salad spinner midge pupa imitation, and I began to probe the likely fish holding lies. In a short amount of time I landed a small brown trout barely longer than my six inch minimum, and it grabbed the perdigon.

Stripe Separate from Cheek

As I began my move to the next attractive spot, I noticed two anglers not more than thirty yards above me. I did not pass another fisherman during my entire inbound hike, yet two competitors showed up within a stones throw of my position! Needless to say I was disappointed, so I stripped in my line and secured it and circled around the invaders of my sacred space.

A Brown Joins the Fun

I hiked .25 mile to give them space, and then I angled back to the creek in a place where I enjoyed decent success in the past. I once again began to probe the pockets, runs and riffles; and I added three rainbows to bring my fish count to four by lunch time a bit before noon. During this time I abandoned the salad spinner and replaced it with a beadhead hares ear nymph and a bright green caddis pupa, but all the action came on the olive perdigon and hippie stomper.  I quickly munched my sandwich and carrots, and then I resumed my prospecting, but guess who I spotted thirty yards above me? It was my nemeses. I saw one of them look back, and they spotted me, so they quickly moved out of sight. I made a mental note of where they were first noticed, and then I fished to that spot and pondered my next move.

Nice Bankside Run

I suspected that they exited and left the next stretch undisturbed, but I could not be sure, so I once again cut over to the trail and worked my way up the path. I found them just downstream of my favorite pool, so I stealthily bypassed them and hoofed quite a distance before re-entering the creek. I estimate that I hiked at least half a mile to allow them space.

As I recall, the fish count was now at six, and during the remaining time on the water, I elevated it to seventeen. The hares ear and caddis pupa failed to generate any action, so I replaced them with a sparkle wing RS2, and I kept the hippie stomper, perdigon, RS2 combination in place for quite a while.

Scene of Rising Fish

At 2PM I approached a gorgeous long pool with a deep run flowing down the center. Just before arriving, I experienced quite a few refusals to the hippie stomper, so I decided to remove the nymphs and transition to a double dry with the hippie stomper and a size 16 olive-brown body deer hair caddis. The caddis fooled one fish, before it created some refusals, and I began to spot a few random rises. My hunch told me that blue wing olives were emerging, so I replaced the caddis with a CDC blue wing olive.

Brilliant

I persisted with the double dry for the next hour, and I added four more trout to bring the total to seventeen. For some reason the stream residents began to smack the hippie stomper, when it was combined with the tiny CDC BWO.

The Workhorse Fly on Sunday

By 3PM I once again bumped up against a trio of anglers, so I decided to call it a day, and I completed the arduous one mile steep ascent from the creek back to the parking lot. The weather was perfect, and I landed seventeen fish, so I cannot complain. Nevertheless, the size of the trout was lacking, with the largest perhaps in the eleven inch range. Oddly the ratio favored rainbows with probably seventy percent of the pink striped variety. The rainbows more than made up for their lack of size; however, with their brilliant colors and spot patterns. I must admit that the competing anglers were a pain, and I missed my normal solitude enjoyed during weekday stream visits.

Fish Landed: 17