The Logan is an almost continuous wave train with only one or two rocks on the entire nine mile stream stretch. There are several intermittent stretches with larger waves and holes but with the exception of the 'White Mile,' the run is almost continuous Class-III whitewater. Outside of the rapids there are several low bridges which can pose a hazard for boaters. (2014 update: the low bridge on the upper Logan was raised a few years ago, and was limbo-able at 1300 cfs in 2011. Below Woodcamp, at flows above 1000 there may be 3 to 6 mandatory roll bridges, depending if you take out at Card or 3rd dam).
Low hanging branches are an additional hazard but are generally not a problem. This is a relatively narrow river, and trees have fallen riverwide across it. At high water, wood can move, and a road scout of Monolith is always a good idea, as it can collect wood. large logs are likely to move as the river reaches seasonal highs.
The first possible rapid of note is the large sliding drop and associated hole a few hundred yards below Ricks Spring, visible from the road. Depending on flow this can be an easy rapid or a exciting slide into a punchable hole. The other section of note is near the bottom of the run. The river picks up gradient for about a mile and some local boaters call it the 'White Mile', followed by Monolith rapid. This is the most difficult section of the Logan and could carry a class V rating at high water, particularly if you are swimming. There are a couple other interesting rapids before Woodcamp, which are hard to see from the road. As a roadside run the Logan has multiple access options.
Christopher Pajak added:
Another class II-III run is upstream (Red Banks section). A couple hundred yards below Ricks Spring, 'the slide' is fun and easy at almost any flow; the hole gets stickier but can always be punched. The 'white mile,' also known as the 'Logan Cave Rapid,' has a few XL holes at high water. Afterward there is a 50-yard break followed by the hardest rapid, 'the Monolith,' which has a large boulder in the middle at the top. Move far right after the rock, then thread your way through the rest staying right most of the way. Then a break for about a mile and another steep straight-away with lots of rocks and holes, you will hit some. You can take out after this at the Woodcamp picnic area/campground or go on to the Card Canyon picnic area. Just above Card is another steep rapid called St. Ann's. It's marked at the beginning by a green bridge over the river.
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Here is a stage and flow forecast for the Logan, updated 2025 (these links seem to change on a regular basis):
Here is a 3 day forecast, and a 10 day outlook from NOAA:
https://www.cbrfc.noaa.gov/dbdata/station/flowgraph/flowgraph\_hc.html?id=LGNU1&ptype=1&linear\_flow=0
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Here are some distances measuring from the bridge at the mouth of Logan Canyon, going upstream.
Right before the bridge is the first dam pond. This is the last reliable cell phone coverage, a public rest room, and a good place to meet.
(Downstream of first dam is the Logan Town section(s), not recommended above 600 for intermediates due to difficulties portaging a large hole below a diversion drop).
0.0 bridge
1.5 New diversion structure, which you should scout for wood if you are running Staircase.
2.0 lower 2nd dam - putin for Staircase, IV+, good above 650 cfs.
2.1 upper 2nd dam, there is a surf wave below the power plant that is good around 400.
2.8 Bridger campground, a putin for some class II, good above 300cfs.
3.3 Another putin for the Bridger section, at a low wood bridge that can be a mandatory roll at high water.
3.9 Upper 3rd dam. A bridge to Spring Hollow campground is a takeout for Woodcamp.
6.8 Card day use area. A good takeout for the Woodcamp section at all levels.
7.1 A good attainment rapid at low flows.
7.4 Chokecherry day use area
7.8 Preston Valley campground. A putin/takeout option, but park out on the main road (campground host will want $ for day use if you park in the campground).
8.1 St Annes rapid; with large gravel pullout on right. Best rapid on Woodcamp section, class III < 600 < IV-
8.2 pullout on right; good low water putin for St Annes to Card; ok at 200cfs.
~8.5 There are a couple large rocks in the river with large wood jams on them. One was almost riverwide in May 2014, but still passable on the right.
9.0-9.3 China Cave cliff on left. Good putin above 300cfs.
9.7 primitive camping
10 Woodcamp campground. Good putin above 350cfs.
(between Woodcamp and Monolith, there are two other IV- rapids that are hard to see from the road).
11.2 Monolith rapid, crux of the upper Logan.
IV- < 650 < IV < 1000 < IV+
11.8 pullouts on right with dirt road, primitive camping spot (bat cave is high up on the cliffs here); putin for a short quality run that includes the white mile, then Monolith, to Woodcamp. 350cfs+ is good, and still decent at 300.
12.9-13.1 more possible putins for Monolith section.
Above here is the 'wilderness stretch', where the river bends away from the road.
13.8 There is a cool cave eddy on the left.
14.6 Temple Fork parking lot, possible putin below the IV- slide.
14.8 The IV- slide mentioned above. Left is a good line.
15.3 Ricks Spring, putin right above here to the Upper Logan. Better above 400cfs. Can putin below Ricks Spring but above the IV- slide if the water is low.
16.3 A putin which has been good at 650cfs, and gives you the best rapid on the Red Banks section.
20.1 Red Banks campground. Putin for the Red Banks to Ricks Spring section, 5miles of continuous class II-III, good above 800cfs. Above here is not paddled much due to private property, possible fences, brush, wood, and braiding. Would probably need over 1200 cfs. (In 2017 this was paddled, with no fences reported.)
22.4 Franklin Basin Road turnoff on the left. Great primitive camping along the Logan headwaters, and the Steep Canyon run, which rarely has enough water. Continuing up Franklin Basin road:
22.7 First Franklin Basin road bridge.
23.1 Great free camping along the creek on the right, for the next few miles.
23.3 Beaver dams.
26.6 Second Franklin Basin road bridge.
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Utah Hydrologic Update for May, 2019, discusses the Logan at 4:50
Most probable level: 1200 cfs, in late May/early June 2019