Transverse Dreams

Transverse Dreams

@transversedreams.bsky.social

A SoCal hiking and skiing blog

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Took a spin up to Grassy Hollow on a crisp October day and was pleasantly surprised to see many of the trees that were totally scorched after the bridge fire have pulled through and have some new green needles on them. Life is resilient.

NWS radar is even picking up these clouds as stationary thunderstorms. Not clear if any rain is really reaching the ground and there is a real dearth of weather stations in the San Gabriels. Basically if radar isn’t catching it no one knows what’s happening between the front range and the desert.

I think if it were storming like that we’d at least see some flood advisories for the burn zones. Though my impression is that if it’s happening above 6000’, NWS LA isn’t too concerned about it (and to be fair there’s 12 million people in their forecast area, of whom almost none are in that zone).

Those certainly aren’t the kind of clouds we’re used to seeing over the San Gabriels but for that atmospheric profile yeah this makes sense!

Transverse Dreams@transversedreams.bsky.social

There’s been some really strange cloud decks over the San Gabriels lately. And despite the high humidity (60 dewpoint) the lapse rate has been high, almost 5! It was 92 in Azusa and 60 at Table Mtn!

There’s been some really strange cloud decks over the San Gabriels lately. And despite the high humidity (60 dewpoint) the lapse rate has been high, almost 5! It was 92 in Azusa and 60 at Table Mtn!

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There’s been some really strange cloud decks over the San Gabriels lately. And despite the high humidity (60 dewpoint) the lapse rate has been high, almost 5! It was 92 in Azusa and 60 at Table Mtn!

This article is a great example of how science evolves, and how we can still learn from the past. As much as we’ve all dreamed of skiing San Gabriel Peak’s southeast gully, the evidence for glaciation in the San Gabriel Mtns is very weak, and it’s now thought the Gabes escaled Quaternary glaciers.

erikbookman.bsky.social@erikbookman.bsky.social

Here's one for the hot season. We may have discussed several years ago. Check graphics in this 100-year-old geology article. www.jstor.org/stable/30063...

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If there were glaciers or permanent snowfields in the San Gabriels in the Ice Age, it would have been high on Baldy’s NE face. I could be convinced though the development of evidence like cirques and moraines is very poor.

First picture, Baldy NE face. Second map, if you do want to see glaciated landscapes in SoCal, the San Bernardino Mountains have you covered! With their north facing slopes and 10000-11000 elevations, these little cirque glaciers fit the bill. Blue- cirques, red- moraines.

This article is a great example of how science evolves, and how we can still learn from the past. As much as we’ve all dreamed of skiing San Gabriel Peak’s southeast gully, the evidence for glaciation in the San Gabriel Mtns is very weak, and it’s now thought the Gabes escaled Quaternary glaciers.

erikbookman.bsky.social@erikbookman.bsky.social

Here's one for the hot season. We may have discussed several years ago. Check graphics in this 100-year-old geology article. www.jstor.org/stable/30063...

View full thread

Still we can learn some things from this paper: Crystal Lake and San Gabriel Peak used to get snow in October, and accumulated a snowpack of several feet in the early 1900s! It’s rare for these elevations to get significant snow these days.

This article is a great example of how science evolves, and how we can still learn from the past. As much as we’ve all dreamed of skiing San Gabriel Peak’s southeast gully, the evidence for glaciation in the San Gabriel Mtns is very weak, and it’s now thought the Gabes escaled Quaternary glaciers.

erikbookman.bsky.social@erikbookman.bsky.social

Here's one for the hot season. We may have discussed several years ago. Check graphics in this 100-year-old geology article. www.jstor.org/stable/30063...

View full thread

Operating in 1926, William Miller didn’t have the framework necessary- plate tectonics- to understand the forces at work in the San Gabriels. The San Andreas Fault had only been conceptualized 20 years before, after the 1906 earthquake, and the power of landslides was also not as well understood.

I kind of think this is the difference between amazing scientists and ordinary people like me- I am able to apply the rules of the system to a given situation; true vision is recognizing the patterns are telling you that you don’t actually understand the rules of the system yet!

This article is a great example of how science evolves, and how we can still learn from the past. As much as we’ve all dreamed of skiing San Gabriel Peak’s southeast gully, the evidence for glaciation in the San Gabriel Mtns is very weak, and it’s now thought the Gabes escaled Quaternary glaciers.

erikbookman.bsky.social@erikbookman.bsky.social

Here's one for the hot season. We may have discussed several years ago. Check graphics in this 100-year-old geology article. www.jstor.org/stable/30063...

View full thread

So what is going on here to create such rugged terrain, and what is pseudo tarn Crystal Lake? The rapid uplift of the San Gabriels over the last 5 million years via compression at thrust faults has resulted in shattered rock masses and rapid erosion.

This and the transform faults that crisscross the San Gabriels have resulted in a landscape of landslides and cliffs. And indeed Crystal Lake is understood to be dammed by a landslide, not a glacial moraine! This is also why the rock climbing in the Gabes is awful compared to the Sierra and Jacinto.

This article is a great example of how science evolves, and how we can still learn from the past. As much as we’ve all dreamed of skiing San Gabriel Peak’s southeast gully, the evidence for glaciation in the San Gabriel Mtns is very weak, and it’s now thought the Gabes escaled Quaternary glaciers.

erikbookman.bsky.social@erikbookman.bsky.social

Here's one for the hot season. We may have discussed several years ago. Check graphics in this 100-year-old geology article. www.jstor.org/stable/30063...

View full thread

This glacier would have had its source at 8000-8500 on the south facing slopes of Islip and west facing slopes of Hawkins - lower than the elevation of Whitney Portal and lower than the lowest glaciated slopes of the South Sierra. It’s alleged foot, at 4000, the floor of Owens Valley!

The top of Eaton Canyon is even lower, 5500. It strains credibility to think such low elevation south facing slopes of the San Gabriels could support glaciers when the Sierra did not. Surely if they had, we’d see even better evidence for glaciers on the north slopes, but we don’t.

This article is a great example of how science evolves, and how we can still learn from the past. As much as we’ve all dreamed of skiing San Gabriel Peak’s southeast gully, the evidence for glaciation in the San Gabriel Mtns is very weak, and it’s now thought the Gabes escaled Quaternary glaciers.

erikbookman.bsky.social@erikbookman.bsky.social

Here's one for the hot season. We may have discussed several years ago. Check graphics in this 100-year-old geology article. www.jstor.org/stable/30063...

Here are a couple of the examples discussed in the article. The most deceptive is Pine Flat, now the site of Crystal Lake campgrounds (first picture). Snowflake = Snowslide Canyon, a great winter descent when it’s in. Second is Eaton Canyon, w a snowflake for the SE gully.

Pine Flat in particular has the shape we’d expect for a glacial cirque, with an alleged tarn (Crystal Lake) to boot. So how do we know Ice Age glaciation is very unlikely here? Well for one thing, the aspect and elevation don’t make sense:

Have you heard the good word of Mt Marcus Baker Thought?

Climatologist49@climatologist49.bsky.social

Whenever there's an atmospheric river pointed at Southcentral Alaska, you should always check the forecast for Mt. Marcus Baker. It is the responsible thing to do. ❄️❄️❄️ forecast.weather.gov/MapClick.php...

Yesterday and today were another two days of reverse clearing for LA County and this is truly the blessed SoCal climate mode. Sunny at the beach to take the chill out of the sea breeze, cloudy in the San Gabriel Valley where it’s a little warmer and drier.

The flip side of living in the foothills, where the marine layer can trap smoke and you occasionally get hot nights if you’re just above the inversion, is that a strong marine layer will get squeezed into honest to goodness precipitation, even in the summer.

Took advantage of some late season June Gloom to try a new mountain bike outing today - the Colby Trail in Glendora. This was a little more reasonable grade for my skills than Van Tassel Motorway and I made it about 1000’ vertical before I ran out of time. The Glendora volcanics outcrop here!

I made it to the top of the Colby Trail at the junction with Glendora Mtn Rd, which I’m too scared to try riding on. Maybe next time I’ll hit upper Colby to Glendora Ridge Motorway, the fire road on the ridge above Azusa!

I made it a little further up Van Tassel Motorway this weekend but it’s so steep, I ended up pushing my bike up a few times because I couldn’t get going. It’s at the outer limits of what’s physically possible with my bike… and my skills.

Transverse Dreams@transversedreams.bsky.social

Boyle Heights structure fire smoke plume from Van Tassel Motorway in Duarte, central San Gabriel Valley.

As if to drive that last point home, at my turnaround point, a much better biker cruised past me going down, with a quick “it’s steep” and then he was gone. In that area I could barely even keep it together going downhill.

One thing I didn’t anticipate about mountain biking is how hard it is to keep control going *up* a steep grade but the physics of it makes total sense. With the bike angled up, almost all the weight is on the back wheel, so the front wheel pops up & it’s very hard to not have it drift to the sides.