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I have a question about Tenaya Canyon in Yosemite. The SummitPost route description for Tenaya Canyon states that the route should only be attempted when water levels are low enough. It is not clear what constitutes a low enough water level to safely descend the canyon via the usual routes. According to USGS water data (http://waterdata.usgs.gov/ca/nwis/uv/?s ... cy_cd=USGS) the current stream flow on the Merced River at Pohono Bridge is about 700 cubic feet per second. This is much more than the historical median of 29 cfs for October 11, but much less than the 2011 maximum flow of 7000 cfs during the spring snowmelt in June.

If anyone here who has experience descending Tenaya Canyon can give us a better idea of what stream flow levels are suitable for descending the canyon, please let us know what you think. Thanks.

Send mrchad9 a "pm", he was there 3 weeks ago.

Water levels should be a non-issue. Of course there are pools and waterfalls, but those are nothing of the sort that would cause hesitation wrt going on a trip now. You could even walk most of the lost valley in the creek without getting wet back in mid September, though the flow is higher now. Water levels should fall fast if it quits raining too.

And I definitely recommend the trip.

mrchad9 wrote:Water levels should be a non-issue. Of course there are pools and waterfalls, but those are nothing of the sort that would cause hesitation wrt going on a trip now. You could even walk most of the lost valley in the creek without getting wet back in mid September, though the flow is higher now. Water levels should fall fast if it quits raining too.

And I definitely recommend the trip.

Thanks for the information on the route. How were conditions in the Inner Gorge when you descended the canyon? Based on the USGS data flows on the Merced River were 100-200 cfs in mid September. Do you think the route you took would be passable if flows were 500 cfs and water levels were 1-2 feet higher? Did you have to swim below Leconte boulder or in other parts of the canyon?

sierradayhiker wrote:Thanks for the information on the route. How were conditions in the Inner Gorge when you descended the canyon? Based on the USGS data flows on the Merced River were 100-200 cfs in mid September. Do you think the route you took would be passable if flows were 500 cfs and water levels were 1-2 feet higher? Did you have to swim below Leconte boulder or in other parts of the canyon?

No problem.

The Inner Gorge was a lot of fun. Water levels weren't an obstacle, and I wouldn't expect them to be if water flow was twice as high either. It wouldn't make the levels twice as deep for example as most of the route where the water affects you is pools and are close to a set depth at anything close to a reasonably low rate. I plan to do the route every year or so now and I wouldn't hesitate at all to go at rates a good bit higher than what I saw, even 4-5 times higher... in most areas the flow wasn't even close to 1-2 feet deep as it was, so I don't think twice the flow would make it much deeper.

I didn't study the route enough to know which is Leconte boulder, but there was no swimming required (though I did go for one during lunch). The second rappel is in a waterfall and will surely get you very wet, and ended in a pool waist deep. That pool might be a few inches deeper now, but most of the route will be in knee deep water at most.

If you are descending you will get a pretty good indication of the flowrate as soon as you cross Tenaya Lake outlet. The flow in the canyon didn't look at all far removed from the outlet flow appearance on my trip.

mrchad9 wrote:

sierradayhiker wrote:Thanks for the information on the route. How were conditions in the Inner Gorge when you descended the canyon? Based on the USGS data flows on the Merced River were 100-200 cfs in mid September. Do you think the route you took would be passable if flows were 500 cfs and water levels were 1-2 feet higher? Did you have to swim below Leconte boulder or in other parts of the canyon?

No problem.

The Inner Gorge was a lot of fun. Water levels weren't an obstacle, and I wouldn't expect them to be if water flow was twice as high either. It wouldn't make the levels twice as deep for example as most of the route where the water affects you is pools and are close to a set depth at anything close to a reasonably low rate. I plan to do the route every year or so now and I wouldn't hesitate at all to go at rates a good bit higher than what I saw, even 4-5 times higher... in most areas the flow wasn't even close to 1-2 feet deep as it was, so I don't think twice the flow would make it much deeper.

I didn't study the route enough to know which is Leconte boulder, but there was no swimming required (though I did go for one during lunch). The second rappel is in a waterfall and will surely get you very wet, and ended in a pool waist deep. That pool might be a few inches deeper now, but most of the route will be in knee deep water at most.

If you are descending you will get a pretty good indication of the flowrate as soon as you cross Tenaya Lake outlet. The flow in the canyon didn't look at all far removed from the outlet flow appearance on my trip.

Thanks, this is very helpful information. One last question - how long did it take to descend the canyon in mid September?

Well, I started at probably 8 or 9 and finished around 6 PM or so (by the time I walked all the way out to the Mirror Lake bus stop). Don't have the exact times as my pics are on another computer.

But note I chose to go slow... my plan was to make it take the entire day as I had nothing else planned later. I sat around enjoying lunch and the canyon for a good while to take it easy.

I noticed that the route description says that the slab traverses/ascents are class four, does that mean they are actually stepper than the half dome cables? Does anyone know what the rock fall is like?

Hi mrchad9, could you contact me asap please (I sent you my cell), thanks.

I'll be calling within the hour.

Osterizer wrote:I noticed that the route description says that the slab traverses/ascents are class four, does that mean they are actually stepper than the half dome cables? Does anyone know what the rock fall is like?

No rockfall. Not steeper than Half Dome from what I remember about Half Dome. I actually didn't find the slabs to be that bad if you go far enough downcanyon before actually descending.

Thanks for the info, I might have to check that out some time. I love Yosemite.

Trip report from two weeks ago.

http://forums.mammothgear.com/showthrea ... 12#post412

mrchad9 wrote:

sierradayhiker wrote:Thanks for the information on the route. How were conditions in the Inner Gorge when you descended the canyon? Based on the USGS data flows on the Merced River were 100-200 cfs in mid September. Do you think the route you took would be passable if flows were 500 cfs and water levels were 1-2 feet higher? Did you have to swim below Leconte boulder or in other parts of the canyon?

No problem.

The Inner Gorge was a lot of fun. Water levels weren't an obstacle, and I wouldn't expect them to be if water flow was twice as high either. It wouldn't make the levels twice as deep for example as most of the route where the water affects you is pools and are close to a set depth at anything close to a reasonably low rate. I plan to do the route every year or so now and I wouldn't hesitate at all to go at rates a good bit higher than what I saw, even 4-5 times higher... in most areas the flow wasn't even close to 1-2 feet deep as it was, so I don't think twice the flow would make it much deeper.

I didn't study the route enough to know which is Leconte boulder, but there was no swimming required (though I did go for one during lunch). The second rappel is in a waterfall and will surely get you very wet, and ended in a pool waist deep. That pool might be a few inches deeper now, but most of the route will be in knee deep water at most.

If you are descending you will get a pretty good indication of the flowrate as soon as you cross Tenaya Lake outlet. The flow in the canyon didn't look at all far removed from the outlet flow appearance on my trip.

Thanks again to everyone who contributed information on the route. There was definitely much more water in the canyon when we attempted the descent last Saturday. The first indication that we were in for wetter than expected conditions was when we pulled into Porcupine Flat on Friday night and found many of the camp sites still covered with snow. When we crossed the outlet of Tenaya Lake near the Sunrise trailhead, the water level was high enough that some of the rocks at the crossing were submerged. We passed more patches of snow along the trail.

Upon reaching Lost Valley we encountered horrible bushwhacking on the sides of the creek. We found that the most efficient way to make progress down the canyon was to hike in the creek, which was 1-2 feet deep in most places and waist deep in several sections. We reached the top of the first rappel at the head of the Inner Gorge. It was not clear if it would be possible to safely descend the waterfalls and slot canyons below given the much higher than usual stream flow for late season, and we thought there was a good chance that continuing the descent would result in an unplanned bivy in the canyon. We decided to turn around and leave the Inner Gorge for another day with more favorable conditions.

Sorry you did not complete your trip but I hope you enjoyed it anyway. What was the recorded flow during your visit? Perhaps I'll see you there in a future year.

I thought the recent snow would ruin it. Did you happen to find a pair of Green Salomon sneakers? They fell out of my pack just before the lost valley.

Do you think the water levels are too high to do the Yosemite Falls cascades or Middle Earth as some people are calling it? I would like to get this in as one last trip before the snow really begins to fall.