Were the recent Los Angeles fires because of climate change?

2024 rainfall in LA was 14.3 inches: slightly below the average for the last 64 years of 15.8 inches per year.

Over the last 64 years the record high rainfall was in 2005 (37.2 inches). The record low was in 2007 (3.2 inches).

2023 was very wet (28 inches). But almost all that water flowed into the ocean even though 10 years ago the citizens of California passed a $10 billion bond measure to fund reservoir building to catch rainwater and store it for firefighting. No reservoir from that bond measure has been completed. This is one of the reasons that firefighters are currently running out of water.

However, even if the LAFD had more water and more equipment and more people they probably still could not have put out these fires once they spread to residential neighborhoods: Houses burn faster and hotter than trees because houses are dry and full of burnable stuff. They send up more embers. And they have large flat radiating surfaces parallel to nearby houses. There are other factors which also cause large fires to spread through residential neighborhoods fast, even though it is easier for firefighters to get close and (normally) to get water.

It almost doesn’t matter how much water the trucks can pump. They cannot stop a large high-wind-driven radiatively-propagating and ember-propagating firestorm.

In this case there were the Santa Ana Winds (SAW) gusting at 90mph. The SAW occur quite regularly in S. Cal. and have been measured at over 90mph many times over the last 20 years. They were famous (mostly because of fires) even when I was a child.

What about the temperatures? The temperatures on 1/6/2025 in LA were 47F (low) and 67F (high). Cool for January in LA.

So, we had a very wet year (2023) followed by a year of average rainfall (2024). We had high winds, but hardly unprecedented, and we had relatively low temperatures as far as I am able to determine.

But we had an under-equipped and under-watered fire department, an ineffective public works bureaucracy (which failed to build reservoirs even with $10B and 10 years to do it), and arguably residential over-building in hilly, wooded areas.

And we have the elephant in the room in California and elsewhere in the USA: For decades the Forest Service and Cal Fire have been largely unfunded to thin trees, clear understory, and do controlled burns - all of which they commonly used to do.

Anyone familiar with firefighting or forestry in California can verify all of the above. The insurance companies verified this when they decided not to renew many California residential fire policies starting in 2022 (unless they were allowed to raise their premiums which the state did not allow).

But sure: It’s climate change.

Lastly here is a map of S. California with the recent fires (small disks) overlaid on the historical fires (irregular regions outlined in black) from the 50 years preceding the era in which most of you were born. California regularly has very large fires.