120 cfs ↑
Rising
25d ago
As the day warms, expect to see some Tricos and good numbers of Baetis through midday into the early afternoon
Conditions
The Big Lost is running low and clear after last week's high water, with flows at 120 cfs in the upper reaches and 261 cfs below Mackay as of September 23. Fish are wary in these conditions, so expect to cover plenty of water with precise casts. Fall Tricos and Baetis are hatching through midday and into early afternoon, and fish are responding in seams, tail-outs, and shallow riffles. Consider smaller flies and lighter tippet in the upper sections, while heavier line and attractors may work near the edges as flows continue to settle through the week.
Gauges
Live cameras
Big Lost River below Inlet Diversion near Arco
USGS 13132520 · Oct 18, 2026, 5:00 PM
Every 60 min · daylight
Big Lost River near Arco
USGS 13132500 · Oct 18, 2026, 5:00 PM
Every 60 min · daylight
Big Lost River near Leslie
USGS 13130300 · Oct 18, 2026, 5:00 PM
Every 60 min · 247
Big Lost River bl Mackay Res nr Mackay
Last updatedUSGS 13127000 · Nov 7, 2025, 10:00 AM
Every 60 min · 247
Techniques
- Look for rising fish in seams, slow tail-outs, and shallow riffles
- Success is dependent on covering a ton of water. Make your first cast count as the fish seldom give you a second chance
- When the bugs disappear, nymph with small Baetis or midge patterns or use Streamers