2021 Update:
There was (another) major fire in the drainage in late 2020 - the largest fire in Colorado's recorded history. An low-water exploratory run in May 2021 found the stream bed clogged with a huge number of strainers, apparently the result of both the recent fire and the earlier High Park fire in 2012.
The Little South Fork is no longer runable. RIP Little South Fork, we enjoyed you while it lasted!
Historical description, so we can have fond memories:
For this run, think small, remote, and wood in inopportune places. Mostly a Class III run with Class V scenery, there are several small gorges that produce most of the excitement. At most water levels, this is a run for boaters that relish wilderness runs. Adrenaline junkies will be disappointed except during very high water, when the character of this run changes and you need a well-developed ability to grab willows instead of eddies. The run used to be tree-clogged, but was flossed and for a brief period was portage-free. Then much of the drainage burned in 2012, followed by floods in 2013.
Assuming there aren’t too many trees, about 1.5 hours into the run you’ll encounter a mini-gorge, not very significant. At about 2.5 hours, watch for the canyon cliffing up; this marks the entrance to a steeper gorge that will get your attention. The crux rapid is maybe another half-hour downstream. This rapid may be difficult to recognize, but in 2014 there’s a tree (mandatory portage) at the top of the gorge. There's a cliff on river left that extends all the way to the water, on a left hand turn. The traditional left-side scout eddy was altered in 2013, and most will portage on right, around two trees and a small log jam. The rest of the run is uneventful, picking up a little gradient before the final plunge just above the confluence with the main stem of the Poudre.
The gauge on the upstream side of the bridge at the putin washed out in 2013. The replacement gauge appears to be very close to the old one. Roughly, < 60 is too low for all but eastern boaters; 60-65 = low; 75-80 = optimal for most; 85-90 = high but good (optimal for confident boaters); > 92 (95?) = too high. Strong boaters have reported that, unlike other nearby runs, this run isn't fun at very high water. High water involves bombing around eddy-less blind corners, worrying about trees, and grabbing willows at the last minute. Of course, your mileage (and comfort level) may vary.
Lat/longitude coords are approximate.
See also,
Big South (Class V/VI),
Joe Wright Creek (Class V),
Spencer Heights (Class V/VI),
South Fork (Class IV/V),
White Mile Run/Upper Rustic (Class III),
Grandpa's Gorge/Lower Rustic (Class III/IV),
The Narrows (Class IV/V/V+),
Upper Mishawaka (Class III/IV),
Lower Mishiwaka (Class III),
Poudre Park (Class IV),
Bridges (Class III/IV),
Upper North Fork (Class IV/V),
Lower North Fork (Class II/III), and
Filter Plant (Class III).