Big Thompson River

Weekly Overview:

August 13, 2020: 

  • Difficulty: Beginner/Intermediate

  • On Tuesday, Big Thompson flows below Lake Estes increased from 260 cfs to 300 cfs. At this level, flows are nearly double the historical average for this time of year. As a result, water clarity decreased and trout are now favoring the banks and soft water. It generally takes trout 2-3 days to adjust to increased flows, so we expect productivity to improve by Thursday or Friday. Hopper droppers and dry droppers fished along the banks and outer seams is a great way to go, right now. Chubby Chernobyl’s, Amy’s Ants, Hippy Stompers and Elk Hair Caddis are all buoyant dry flies that will hold 1-2 nymphs but also attract surface eats. Trail a Pat’s Rubber Legs, Iron Sally, red Copper John, Guides Choice Hares Ear, Pheasant Tail or Rainbow Warrior, 12” – 24” behind your dry. Big and flashy will be the key until clarity improves. If you’re not seeing any action, you can either trail a second nymph or add a little weight. If you fish the faster and deeper water, a heavy nymph rig will be necessary. Baetis emergers and caddis pupa have been great trailer patterns lately, so make sure to have some Sparkle Pupa’s, Sparkle Wing RS2s, Darth Baetis and Barr’s Emergers on hand. 

    • Ideal Days to Fish: Monday, Saturday & Sunday

  • Suggested Flies:

    • Sub-surface: RS2 (#20-22), Barr's Emerger (#20-22), JuJu PMD (#20-22), Barr's Emerger (#20-22), Chocolate Thunder (#20-22), JuJu Baetis (#20-22), Mercury Pheasant Tail (#20-22), WD 40 (#20-22), Mercury Midge (#22-24), Black Beauty (#22-26), Zebra Midge (#20-24), Blood Midge (#20-22), Disco Midge (#20-22), Guides Choice Hares Ear (#16-18), red Copper John (#18-20), Rainbow Warrior (#18-20), Pat's Rubber Legs, pink/green scud, leech pattern and San Juan Worm.

    • Surface: Parachute Adams (#22-24), Parachute PMD (#22-24), Griffiths Gnat (#22-24), Little Black Caddis (#16-18), Chubby Chernobyl (#12-14)

Detailed River Info:


The Big Thompson, commonly referred to as the Big T, is a beautiful river that originates high in Rocky Mountain National Park. This small-medium sized river flows through Rocky Mountain National Park and the town of Estes Park before feeding into Lake Estes. Below Lake Estes, the river continues along Highway 34 through Drake, eventually making its way to the town of Loveland. The Big T flows through various types of terrain, offering anglers a variety of scenic and fishing opportunities. The stretch of river that flows through Rocky Mountain National Park is in an open meadow setting and contains brown trout, rainbow trout, brook trout and if you’re lucky, greenback cutthroat. Below Lake Estes, anglers will find themselves in a canyon setting dominated by pocket water with a select number of deep pools and runs. Brown and rainbow trout in the 10 – 12” range can be found in this stretch.


The Big Thompson is a diverse river that is friendly to anglers of all skill sets. The stretch that flows through Moraine Park in Rocky Mountain National Park is highly sought after during the summer months. During the summer, this stretch tends to see a lot of foot traffic, so stealthy fishing is required to not spook the trout. Fishing dry and dry dropper setups is the preferred method in Moraine Park. Below Lake Estes, pocket water is prevalent, which may test your ability to fish tight pockets. Nymphing is a productive method year-round, while dry and dry dropper setups are productive during the summer and fall. Overall, the ideal time to fish the Big Thompson is during the summer and fall months. However, if you’re looking to fish during the winter, the section directly below the Lake Estes/Olympus Dam is classified as a tailwater and usually remains ice-free.


River Access:

The Big Thompson has many access points with varying levels of difficulty. In order to fish Moraine Park, anglers will need to purchase a $25 National Parks day pass. Moraine Park is located just under 3 miles from the Beaver Meadows Entrance Station on the south side of Estes Park. Below Lake Estes, anglers can access the tailwater section via a public park on Mall Rd. Downstream of the tailwater, there are a number of pull offs along Highway 34 that anglers can use to access the river.  Be conscious of private property when fishing along Highway 34. In general, the bank that borders the road is public and the property along the far bank tends to be private.

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