Current JMT conditions (snow) Mammoth to Tuolumne 5-21-2015 | High Sierra Topix  

Current JMT conditions (snow) Mammoth to Tuolumne 5-21-2015

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Current JMT conditions (snow) Mammoth to Tuolumne 5-21-2015

Postby filmoreslim » Thu May 28, 2015 7:30 am

Just a quick conditions report for this trail which I trekked with two friends, one of which really struggled with conditioning and altitude.

Preface logistics: We stayed in Mammoth on Thursday night prior to Memorial Day Weekend. Drove over Tioga Road from San Francisco Thursday, as soon as we got through the pass closed due to snow. We rented a car at the Mammoth Lakes Airport that day to shuttle my car back to Tuolumne early Friday. We got a late start Friday as the pass was still closed till about noon. After we shuttled my car to Tuolumne and returned the car to the Airport, the Westin was kind enough to pick us up for free and drive us to the trailhead - the ranger almost did not let us in because the Westin does not have a permit to operate on federal lands commercially. But the shuttle to Devil's Postpile was not running so they let us in.

Since we started late, we left from Agnew Meadow instead of our intended starting point of Devil's Postpile. We linked up with the JMT at Shadow Lake. We encountered an attractive female USFS ranger about 25 years old who checked our permit about a mile in - our permit was for entry at Devil's Postpile North and we were on the Shadow Creek trail - thought there might be problems but she either did not notice or understood our logistical issues.

So we missed the JMT from Devil's Postpile to Shadow Lake. I would not anticipate any issues there besides the usual downed trees this early in the season. There was snow on the trail above 9000' in shaded and north facing spots. The places where you could encounter a difficult experience are as follows:

1. Emerald Lake: The JMT goes to the West of this lake, a small lake just before 1000 island lake. Unless you have snow shoes, the trail is impassable to the west of the lake due to deep snow. We were forced to go around the east side of the lake, still in significant snow, post-holing for about an hour. We followed the JMT up above 1000 island lake - the trail that follows the lake looked to be full of snow - the lake was 80% covered in snow and ice.

2. After passing Rush Creek on the approach to Donahue Pass, the JMT follows the West side of a creek (not sure of the name). The West side of the creek is full of deep snow banks and snow bridges across the boggy meadow features that are commonly found in the sierras at high elevations near passes (the trail is not recognizable). The snow may seem to be 4-6" deep and then you could post-hole up to your hip if you step in a spot where there is a small creek running underneath. We encountered a solo JMT hiker who was complaining that it took her several hours to get over the pass and down through this area. I quickly recognized that even though the trail followed the West side of the creek, the East side of the creek was more sun exposed so we crossed and found it much easier to walk around deep snow banks. We camped at the end of the meadow near the last stands of trees before the pass.

3. The trail is covered in snow up the south side of Donahue Pass (10,250'-11,0000) and down the north side to about 10,000'. We hiked up Donahue Pass in the early morning with crampons and hard snow. If you attempt to cross the pass on the south side in the late morning/afternoon, you will be post-holing in deep snow. You can also take a high traverse on the east side of the pass negotiating boulders and talus and avoid 70% of the snow. The snow on the North side of the pass is much deeper and uniformly exists until after you cross the Lyell Fork.

4. Deep, soft snow drifts exist below the Lyell fork down almost until the meadow. Use caution.

We hiked up and over Donahue Pass with crampons in hard snow. I would have needed them if the snow around Emerald Lake was hard - we traversed the lake in the afternoon hours so the snow was soft. For the next 7-14 days, snow shoes or crampons (with gaiters) are highly recommended for the limited areas discussed above.
Last edited by filmoreslim on Thu May 28, 2015 4:33 pm, edited 2 times in total.



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Re: Current JMT conditions (snow) Mammoth to Tuolumne Meadow

Postby oldranger » Thu May 28, 2015 8:17 am

Conditions seem almost the same as last year on Memorial day weekend in this area except the snow is new and unconsolidated. Same amount of ice on 1000 Island lake. Wish I was in California now as I was last year as I think the next month will be the best of the summer for backcountry travel. (mosquitos don't bother me and are usually an indicator of good fishing and good flowers.)

Mike
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Re: Current JMT conditions (snow) Mammoth to Tuolumne Meadow

Postby filmoreslim » Thu May 28, 2015 9:24 am

I made an edit, my morning coffee had yet to kick in when I originally wrote this. The approach to Donahue Pass should be off-trail on the east side of the creek (edit already made) not the west side.

Throughout the trail the snow is consolidated, spring snow, but in the afternoon, the snow is soft and wet. The snow pack is taking a lot of rain...there were no significant new accumulations over labor day weekend or the days leading up that I could see in the snow pack. It looked like there might have been 3-4 new inches on Wed prior but that snow definitely blew around and then got rained on. The morning we crossed was preceded by a clear, cold night with a low temp in the high 20's so there was a solid re-freeze.

Plan to get over Donahue Pass in the AM if you want to spend less energy in snow.
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Re: Current JMT conditions (snow) Mammoth to Tuolumne Meadow

Postby maverick » Thu May 28, 2015 11:45 am

Thanks Chris for taking the time to post this, I am sure it will be very useful. PM sent.
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Re: Current JMT conditions (snow) Mammoth to Tuolumne Meadow

Postby GreenhornBackpacker » Thu May 28, 2015 1:35 pm

I want to take some dayhikes around Mammoth next week. How was the trail up to Shadow Lake? Muddy, icy? Was there anyplace where deep water was an issue such as near Olaine Lake or in Agnew Meadow? Do you have any information from other hikers or what you observed about the trail up to Ediza?

Thanks for posting.
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Re: Current JMT conditions (snow) Mammoth to Tuolumne Meadow

Postby maverick » Thu May 28, 2015 2:12 pm

Hi Green,

I want to take some dayhikes around Mammoth next week. How was the trail up to Shadow Lake? Muddy, icy? Was there anyplace where deep water was an issue such as near Olaine Lake or in Agnew Meadow? Do you have any information from other hikers or what you observed about the trail up to Ediza?


The OP wrote:
There was snow on the trail above 9000' in shaded and north facing spots.


Shadow Lake is at 8737, and Olaine Lake is at around 8000 ft, neither area should be an issue. OP wrote that there snow was above 9000 ft, the JMT junction above Shadow is at 9000 ft, and stays above 9600 ft all the way to 1000 Is Lake. Agnew is at 8300 ft.
Called Mammoth Lakes Wilderness Center, they also say it is all clear, no snow or flooding in the areas you are inquiring about GB.
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Re: Current JMT conditions (snow) Mammoth to Tuolumne 5-21-2

Postby rams » Sun May 31, 2015 9:46 am

I did a dayhike yesterday from Agnew Meadow to Island Pass via the River Trail on the way in and the PCT on the way back. If you take this route to see Thousand Island Lake, you will have pretty much zero issues with snow to the lake (a bit at the pass though), though the trail has mud and puddles in many places (more so on the PCT and the area near Island Pass). There were patches of snow right before the lake that were maybe 20 feet long and trivial to walk around. It felt like summer. The areas towards Garnet Lake/Minarets/the JMT that filmoreslim reported on seemed to have significantly more snow. Thousand Island Lake lost a lot of ice since filmoreslim's original report and was maybe 30% ice covered (and lost a noticeable amount of ice between my arrival at Thousand Island and my departure after returning from the pass). Island Pass had a bit more snow than Thousand Island and the trail disappeared in places, but a detour of maybe 100 feet was the most I had to do just past the ponds at the pass. I didn't go any farther.

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decent flow in the rivers


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outlet of Emerald Lake (I believe) from the River Trail...not much snow here but just above the ridgeline there was much more (as viewed later from above Thousand Island)


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approaching Thousand Island Lake...very little snow


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overlooking Thousand Island Lake...lost a lot of ice since the original report from May 21


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more snow towards Garnet and the Minarets compared to Thousand Island


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very minor flooding (very easy to circumvent) or water crossings throughout the hike...this is at Island Pass


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rivers eating away the snow at Island Pass


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the worst snow crossing I encountered at Island Pass (just went around it to the right)
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