Z.W. Wolf
Senior Member.
What is the cause of these massive wildfires and fires in suburban areas.?
I'm going to start with a post about what the reality is. These factors have come together:
-Two wet years which caused significant plant growth.
-Lack of rainfall during the first months of California's wet season - October to April
-Above normal temperatures for several months.
-Unusually severe winds.
Singly, these factors would be significant. Together, they are critical.
This article was written shortly before the fires started.
https://www.latimes.com/california/...y-enters-drought-as-forecast-remains-bone-dry
A Summary (not quotation)
https://www.npr.org/2025/01/08/nx-s...event-was-anything-but?utm_source=chatgpt.com
Santa Ana winds, a regular phenomenon in Southern California during colder months, have been playing a significant role in fueling the massive wildfires in the region. These winds originate when high-pressure systems form over the Nevada and Utah deserts, driving air westward toward California's coastal mountains. As the air descends from the mountains, it compresses and heats up rapidly—warming by about 10 degrees Celsius per kilometer of descent. For instance, air descending two kilometers can warm up by 20 degrees Celsius, or roughly 36 degrees Fahrenheit, creating hot, dry, and fast-moving winds.
The winds further accelerate as they descend to the valleys, funneled by mountain ranges much like how wind speeds up between city blocks. This effect, explained by experts like Mingfang Ting of Columbia University and Mike Wofford of the National Weather Service, results in particularly strong and impactful winds. Normally confined to specific areas, this year's Santa Ana winds have been unusually widespread and intense, reaching areas like Pasadena, which typically experience no winds during such events.
Mike Wofford described this year's Santa Ana winds as being "on steroids," significantly more destructive and covering a larger area than usual. While the strongest winds have passed, their lingering effects, combined with ongoing wildfires, present a persistent danger. Santa Ana winds often continue into spring, meaning the risk of wildfire will remain if dry conditions persist. This combination of factors underscores the challenging battle firefighters and residents face in mitigating the effects of these extreme weather events.
Other factors
-These suburban areas adjoin rural areas and are built on steep topography.
A dangerous place to build and live. Neighborhoods in flood zones are going to flood, and neighborhoods in hurricane zones are going to be destroyed by hurricanes. These neighborhoods are built in fire zones. They're going to burn sometime or other.
The more southern parts of Altadena less so. I'm guessing that the wind pushed airborne burning material down into that area.
-Inadequate infrastructure.
https://www.nationalgeographic.com/environment/article/los-angeles-wildfires-water-scarcity
This is the JPL campus. The tanks to the north are water tanks. A really familiar sight in S. Calif. (That's where I'm from btw.)
This kind of tank is what supplies water to the neighborhoods built on and around the hills. Water is pumped into them, and gravity generates water pressure. Once they run dry, it's a long process to fill them. With the water pressure reduced in the general system, that process took longer.
These tanks are there above neighborhoods to do the wash and water the lawn. The fire hydrants in the area are meant to supply water to fight ordinary house fires. This mundane infrastructure completely collapsed in some areas. I'm skeptical that this made any real difference. This kind of massive event couldn't be contained by fire engines and hoses.
Most of the tanks in question were filled before the winds came along, but they're not very big.
https://www.independent.co.uk/news/...rnia-fire-hydrants-la-reservoir-b2677454.html
-Aerial tankers were grounded by severe winds for some time in some places.
https://www.independent.co.uk/news/...rnia-fire-hydrants-la-reservoir-b2677454.html
I'm going to start with a post about what the reality is. These factors have come together:
-Two wet years which caused significant plant growth.
-Lack of rainfall during the first months of California's wet season - October to April
-Above normal temperatures for several months.
-Unusually severe winds.
Singly, these factors would be significant. Together, they are critical.
This article was written shortly before the fires started.
https://www.latimes.com/california/...y-enters-drought-as-forecast-remains-bone-dry
Much of the region, including the majority of Los Angeles, San Bernardino, Riverside, Orange and San Diego counties, has fallen into moderate drought conditions, according to a U.S. Drought Monitor map released this week. The last time the Southland saw similarly dry conditions was in early 2023, as the state was exiting a punishing, years-long drought thanks to an exceptional kickoff to the wet season.
Prior to the recent drought report, conditions in Southern California were considered to be "abnormally dry" for the last few weeks. Much of the Central Valley remains in that category.
"Above-normal temperatures and below-normal precipitation resulted in expansion of drought in Arizona, California and Nevada," the new report said.
"Typically we see, at this time of year, close to 4 inches of rain, which would usually be enough to squash any significant fire weather concerns," Kittell said. "But because we haven't had anything close to that, and because we've had a really active two years [of plant growth] ... there's a lot to burn."
He said more red flag warnings are likely to be issued, which were in place in December when the Franklin fire in Malibu broke out, and in November when the Mountain fire tore through southern Ventura County.
A Summary (not quotation)
https://www.npr.org/2025/01/08/nx-s...event-was-anything-but?utm_source=chatgpt.com
Santa Ana winds, a regular phenomenon in Southern California during colder months, have been playing a significant role in fueling the massive wildfires in the region. These winds originate when high-pressure systems form over the Nevada and Utah deserts, driving air westward toward California's coastal mountains. As the air descends from the mountains, it compresses and heats up rapidly—warming by about 10 degrees Celsius per kilometer of descent. For instance, air descending two kilometers can warm up by 20 degrees Celsius, or roughly 36 degrees Fahrenheit, creating hot, dry, and fast-moving winds.
The winds further accelerate as they descend to the valleys, funneled by mountain ranges much like how wind speeds up between city blocks. This effect, explained by experts like Mingfang Ting of Columbia University and Mike Wofford of the National Weather Service, results in particularly strong and impactful winds. Normally confined to specific areas, this year's Santa Ana winds have been unusually widespread and intense, reaching areas like Pasadena, which typically experience no winds during such events.
Mike Wofford described this year's Santa Ana winds as being "on steroids," significantly more destructive and covering a larger area than usual. While the strongest winds have passed, their lingering effects, combined with ongoing wildfires, present a persistent danger. Santa Ana winds often continue into spring, meaning the risk of wildfire will remain if dry conditions persist. This combination of factors underscores the challenging battle firefighters and residents face in mitigating the effects of these extreme weather events.
Other factors
-These suburban areas adjoin rural areas and are built on steep topography.
A dangerous place to build and live. Neighborhoods in flood zones are going to flood, and neighborhoods in hurricane zones are going to be destroyed by hurricanes. These neighborhoods are built in fire zones. They're going to burn sometime or other.
The more southern parts of Altadena less so. I'm guessing that the wind pushed airborne burning material down into that area.
-Inadequate infrastructure.
https://www.nationalgeographic.com/environment/article/los-angeles-wildfires-water-scarcity
Over the past decade, California has experienced historic drought conditions, which have resulted in water-restricting policies. And while the past two rainy winters have offered some reprieve in Southern California, 2025 has been off to a record-dry start. Climate scientist Daniel Swain referred to this swing between extreme rain and drought as "hydroclimate whiplash," which his research found is exacerbated by global warming.
While this boom-bust precipitation cycle creates particularly dangerous conditions for fires, it has allowed for California to see its previously shrinking water reserves fill in recent months. So while drought has been a persistent problem in Southern California, it wasn't behind the cause of the city's water shortages. It also can't be chalked up to restrictions protecting the endangered Delta smelt, a tiny fish that has proved to be a perennially politically popular scapegoat for water issues. The fish's protected status limits water usage in its Sacramento–San Joaquin River Delta habitat, which some have argued should be freed up for human consumption.
Quiñones instead explained it as an issue of access.
During that roughly 15-hour window from the Palisades Fire sparking and the available water tanks running dry, Quiñones said the demand for water was four times the norm, causing water pressure to lower. This made it difficult to achieve the force needed to get water into the higher-elevation tanks, particularly at the rate necessary to address a fire moving five football fields a minute, boosted by the gusty Santa Ana winds.
"We pushed the system to the extreme," Quiñones said during a Wednesday news conference. "We're fighting a wildfire with an urban water system. And that is really challenging."
This is the JPL campus. The tanks to the north are water tanks. A really familiar sight in S. Calif. (That's where I'm from btw.)
This kind of tank is what supplies water to the neighborhoods built on and around the hills. Water is pumped into them, and gravity generates water pressure. Once they run dry, it's a long process to fill them. With the water pressure reduced in the general system, that process took longer.
These tanks are there above neighborhoods to do the wash and water the lawn. The fire hydrants in the area are meant to supply water to fight ordinary house fires. This mundane infrastructure completely collapsed in some areas. I'm skeptical that this made any real difference. This kind of massive event couldn't be contained by fire engines and hoses.
Most of the tanks in question were filled before the winds came along, but they're not very big.
https://www.independent.co.uk/news/...rnia-fire-hydrants-la-reservoir-b2677454.html
A patchwork of municipal waters systems feed L.A., drawing water from 200 different utilities, supporting a system designed to handle lower-level, urban fires, not multiple large-scale wild fires descending from the hills.
"We are looking at a situation that is just completely not part of any domestic water system design," Marty Adams, a former general manager and chief engineer at the Los Angeles Department of Water and Power, told The New York Times. "If this is going to be a norm, there is going to have to be some new thinking about how systems are designed."
"It was like a worst-case scenario, but I think we should be planning for those worst case scenarios," Faith Kearns, a wildfire and water expert at Arizona State University, added in an interview with National Geographic. "You can't predict everything, but also, I do think this is where we're headed."
Faced with a series of fires moving as fast as five football fields per minute, this system buckled.
By Wednesday, three 1 million gallon, high-elevation water tanks supplying the hard-hit Pacific Palisades went dry. High demand not only drained the tanks, and drew from water that would've been used to replenish them, but it also lowered pressure within the overall hydrant system, further straining the ability of firefighters to quickly get water.
"We had a tremendous demand on our system in the Palisades," Janisse Quiñones, chief engineer at Los Angeles Department of Water and Power, said at a Wednesday briefing. "We pushed the system to the extreme."
Some of that demand would've been met by a 117 million gallon reservoir complex in the Pacific Palisades, but it sat out of use for repairs as the fires in the Palisades began. Officials estimate that had the Santa Ynez Reservoir been online, it would've cut demand on the area's water system from four times to three times as high as normal.
"You still would have ended up with serious drops in pressure," former Department of Water and Power general manager Adams told The Los Angeles Times. "Would Santa Ynez [Reservoir] have helped? Yes, to some extent. Would it have saved the day? I don't think so."
-Aerial tankers were grounded by severe winds for some time in some places.
https://www.independent.co.uk/news/...rnia-fire-hydrants-la-reservoir-b2677454.html
Making matters worse, the high winds that helped spread the fires also temporarily prevented officials from using aerial drops of water which could've been pulled from the ocean or Southern California's reservoirs, which are currently sitting above historical levels.
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