Mammoth Mountain, CA May 26-28, 2025

[jamesdeluxe]

The dead tree stumps in foreground were killed by a surge of carbon dioxide like that which killed those patrollers at the fumarole.

Where did the carbon dioxide originate -- directly underneath? To take out trees like that, wouldn't it need to be either a) incredibly concentrated or b) persisting over a long period of time? If a), wouldn't that area be cordoned off like the fumarole or is there a skull-and-crossbones sign nearby?

 

[tseeb]

Was there sections of deep snow on Tioga? Didn't look that way from your pics.

Only at the very top as seen to the right in my photo at entrance station. There was at least a couple feet of snow on ground between there and 13K' Mt Dana, but the W-facing slopes had mostly burnt off. There was little snow in open areas on right/N of highway in 8600' Tuolumne Meadows although it looked swampy for hiking unless on boardwalks. More snow was left under trees on S side of highway. On my last trip over Tioga (late July 2023), I took photo of skiers coming down close to Ellery Lake where snow already looked thin close to lake for doing that this year.

 

[Tony Crocker]

is there a skull-and-crossbones sign nearby?

The most widespread patch of dead trees is just left of the top of the lake in the picture, next to the parking lot!

 

[EMSC]

Here is a view down that couloir when a friend and I skied it in near-ideal conditions. I believe this was February 2024.

I feel like you need to be especially confident in the avi conditions for that line. Unlikely any chance of survival if an avi drains you directly into the lake.

 

[ChrisC]

The Eastern side of the Sierra finally gets some love from the press:

The Other Great California Road Trip
With natural disasters plaguing the iconic Pacific Coast Highway, a local recommends Highway 395—for alpine lakes, cozy cafes and desert ghost towns along the Sierra Nevada’s dramatic eastern side.

LINK

 

[snowtrekker]

I feel like you need to be especially confident in the avi conditions for that line. Unlikely any chance of survival if an avi drains you directly into the lake.

Agreed. There is a decent alluvial fan between the mouth of the chute and the lake, but still not the exposure you’d want in a big slide.

We only considered it after the avi forecast was downgraded to “low” that morning after an extended period of no signs of instability for the main problems of concern at this elevation and aspect. The first party that put in those tracks was about an hour ahead of us. We also spent a while navigating to the entrance, looking g for signs of instability on similar aspects. Fortunately other lines in this area are less consequential and see plenty of traffic, so reports are easy to come by and there are multiple bail-out options off the peak.

 

[snowave]

Where did the carbon dioxide originate -- directly underneath? To take out trees like that, wouldn't it need to be either a) incredibly concentrated or b) persisting over a long period of time? If a), wouldn't that area be cordoned off like the fumarole or is there a skull-and-crossbones sign nearby?

An acquaintance/friend of both TonyC and I (who was a forest ranger at the time) nearly died in that area back in 1994.

Here's an article that was written at the time: https://www.latimes.com/archives/la-xpm-1994-11-27-mn-2187-story.html

 

[EMSC]

An acquaintance/friend of both TonyC and I (who was a forest ranger at the time) nearly died in that area back in 1994.

I was going to say I thought that they monitored the CO2 levels in that area pretty consistently in modern times? Both for keeping people out when needed and for scientific study.

 

[snowave]

I was going to say I thought that they monitored the CO2 levels in that area pretty consistently in modern times? Both for keeping people out when needed and for scientific study.

After that incident in 1994, yes... however I think it was somewhat limited before then, even though they knew CO2 had increased after the 1989 quakes.