Why does Los Angeles have so many bad fires?

Wildfires in the Los Angeles area are common, and a particularly intense set of fires are burning right now due to weather conditions specific for the area. Just like mountains can focus rainfall to cause floods, they can also dry air out, which creates drier vegetation and sets the stage for easier burning and spreading. This video talks about how a specific weather setup and a huge mountain range east of Los Angeles combine to occasionally create an environment in which fires can grow and spread explosively. Video also talks about how this process is like the opposite of the Hurricane Helene flood, and whether or not climate change might make these events worse.

[nothanks]

The Bob Ross of Geology. Seriously though, love your content, I learn so much.

[cherylb]

You do a fantastic job of helping us understand what's happening

[christianhunt]

I like the way these disaster videos highlight the interface between geology and meteorology!

[MarylandResident]

Another banger from the best mustache in geology.

[carolyng]

Thank you Phillip for another fascinating explanation of the interaction between geology, topography and weather!

[skybluskyblueify]

I've been watching coverage of the LA disaster/s over the last few days but this coverage is the only one that made it crystal clear. Maybe I was softened up by TV-style news and YT weather specialist channels, but boy was this vivid and understandable.

I've watched all of your Helene coverage and that was so clear it was like watching it happen in reality with a god's-eye view. To tie both of their phenomena together has made all of this unforgettable.

Schools need this kind of instruction rather than dry books as flat as a pancake(or worse).

Keep up the great work and maybe people will pay well for your instruction.

[johnanthony]

Without a doubt, my favorite channel on YouTube.

[ThePecadillosam]

SoCal retired geologist here… good discussion of the basic geology of the LA Basin and surrounding mountains. Regarding Climate Change, a couple of things: the jet streams that bring us rain in SoCal are staying north this winter (our rainy season)…we haven’t had measurable rain since last May. Also, the seasonal precipitation pattern is increasingly a boom or bust with climate change. We had record precipitation locally in the winter of 2022-2023 (including 15 feet of snow in Big Bear), and this year zero, now well into January, with nothing on the horizon.

[benda]

You are better than the best teachers I had in high school or college.

[carriegarrisonvos]

Truly enjoy your videos!! I learn so much from them and they help make sense of horrible disasters we all seem to be experiencing these days. One woman I work with has a sister and her family who evacuated, and two friends lost their houses. It was horrifying to watch yesterday and today. Brought back a lot of feelings from when Helene hit here. Thanks so much for keeping us informed and learning!

[tiffanycechowicz]

Always incredibly valuable. Thank you for your time and work!

[Chainsaw-ASMR]

You are a fantastic educator and I’m really happy that I found your videos after Helene. Keep doing what you’re doing!

[Siethon]

Top notch drawings, descriptions, and analysis. Thanks!

[wayloncapps]

I’ve always heard about how dry this area is and knew that the wind was a part of the reason. It’s so interesting the reason why. Thank you. Keep up the good work

[johnlord]

As having lived (and still living) from San Diego to SanFran, this California geology is highly tectonic but also adiabatic. The Los Angeles to Baja peninsula is the latest modern detachment of land mass from the Mexico landbridge. It is held in check right now with the basalt triangle of the Grapevine, that lately has had massive swarms to the east of its geology. The Central Valley north of the Grapevine, has higher humidity from the agriculture's aspiration of water (much like the insane and intense humidity of 90 percent and 90+ F of the Midwest, been there, done that ... don't do that stoopid !). The intense heat of the Central Valley then rises and is forced into the said circular pattern for the high desert Nevada winds (cold in winter, extreme hot in summer) being pushed down into the Los Angeles mountains and plains. Here in SanFran, I found a 3 - 3 1/2 day weather cycle, all year, in which there is onshore winds and weather that pushes into SanFran Bay, up the Sacramento/San Juaquin River and over the Livermore-Tracy coastal hills, pushing up to Lake Tahoe and Reno into the Nevada desert. The then responsive weather pattern of Nevada responds and changes a reverse flow back down into SanFran Bay and having an offshore wind flow. In winter, this freezes SanFran from the Nevada high desert cold weather, while we moderate Lake Tahoe/Reno temperatures. In summer, our cooler coastal weather cools Lake Tahoe/Reno, and Nevada sends back insane heat into the Bay.

All of these coastal mountains formed from the ancient Farallon plate, pushing north and spinning the North American craton from being 66 MYA W-E alignment of the Rocky Mountains (orogeny in 80 MYA), to its current N-S alignment. Then compression of the shorelines created the inner Cascades (plate tectonics subduction process). Coastal mountains were then scrunched. All of the Oregon/California mountainous Siskiyou/Klamath overburden basalt sitting atop a 5 super magma chambers (of the same size and volume as Yellowstone !), and that of the northward moving LA-Baja peninsula scrunching up under the Grapevine. The SanFran fault zone land mass and the San Andreas fault zone landmass sit confronted at the Siskyou-Klamath mountains. If either the Siskiyou or the LA Grapevine ever snapped, then the suspected M9 earthquakes and the entire California shoreline, coastal mountains, and Baja peninsula will be caterpillar crawling in jerks and bumps until it smashes up against the Canadian Shield, becoming the whole new shoreline and double coastal mountain ranges of the Pacific Northwest.

The current weather patterns develop with the Santa Ana winds pushing from the south-eastern Death Valley et al region and the Salton Sea and lower basin of the Coachella Valley (Coachella - Brawley towns north and south of the Salton Sea) swirls and push out to San Diego but also up to the Grapevine and Los Angeles. It is the Southern California high desert region crossing over to Arizona or Nevada, in which I have sat at Ontario, California, waiting to go up to Apple Valley and over to Arizona in an 18 wheeler, and the winds were so strong that they literally smashed up against the sides of all the parked tractor-trailers lifting up one side, and then slamming them down - repeatedly. I definitely didn't get any sleep that night - and the lettuce load from the Grapevine to Las Vegas was entirely tossed and banged into smithereens. I have driven 18 wheels eastward across the Anza Borrego mountains San Diego to Yuma Arizona and was almost literally-pushed sideways to the local bridge's guard rail in less than 40 feet. I have also been with a car, going westward across the Anza Borrego mountains, south of Brawley, and having 80 MPH winds pushing eastward (!) and following an 18 wheeler as a wind flow reduction, and it dragged on him. He returned the favor, when I was able to pass him, and he USED ME as his wind buffer and my gas pedal was pushed to the floor trying to maintain any speed, while he was enjoying the wind flow at my expense !

[ArtHistorianVictoria]

Thank you. So clear and easy for us geology enthusiasts. My mom and I were wondering about the Fjords of Norway. Would love to see you offer a presentation about their origins/creation. Maybe a future video idea?

[kruelunusual]

Nice to see this. Not the fires, the enlightenment!

[donnaguy]

I was in 5th grade for the Chicago '67 Blizzard. They had forecasted 1-2" or something trivial like that. We were sent home from school early. I can't remember what day of the week it was but we had at least one snow day out of it. Chicago was hit pretty hard in 1978. Chicago was shut down. I remember tripping on a parking meter. The sidewalks were that covered! Sometimes, we would be walking on the little trail created by people just walking over & over in the same place. Often, you'd find yourself in the middle of the street, walking on top of cars that were buried. It was crazy! It cost Mayor Blalandic his job. Jane Byrne ran & beat him soundly.

[macpduff]

You are speaking about the canyon effect - the same as Manhattan in the winter When moving air is forced between narrow areas, the wind accelerates

[gustavderkits]

Excellent again. The contrast against the Appalachian landslides is perfect. The Appalachian mountains are some of the oldest and the San Gabriel range is being built while you watch. The landslides in the nearby Rancho Palos Verde area is due to that area being unstable because it has been scraped up from the ocean floor. It’s full of shells. The contrast of the airflow physics is clear as well.