Which of those named weather events was outside of historical experience in the area?
From the outside, wet years and dry years and desert winds seem very much like the expected climate for SoCal.
From the outside, wet years and dry years and desert winds seem very much like the expected climate for SoCal.
Over the last few decades averages for events have changed, and not for the better:
> It was found that nearly all the observed increase in burned areas over the past half-century is due to human-caused climate change. It is estimated that from 1971 to 2021, human-caused climate change contributed to a +172% increase in burned areas, with a +320% increase from 1996 to 2021. In the coming decades, a further increase in annual forest burned areas is expected, ranging from 3% to 52%.
* https://www.drought.gov/news/study-finds-climate-change-blam...
The paper, which looks quite good, amounts to (stationary baseline + climate drift) explaining burning more than (stationary baseline) alone.
From the paper...
> Their respective uncertainty bands overlap for most of the time periods considered; however, starting in 2018, there is a complete separation between CMIP6-ALL and CMIP6-NAT scaling factor distributions suggesting a complete dominance of anthropogenic over natural forcing.
...or incorrect models or uncertainty bands. The paper looks good but like it presumed to find the desired results from the research outset.
Beware anything done with simulations that provides 3 significant digits (172% increase!). I don't doubt the influence of climate but I do doubt the certainty of these authors.
Going back to the GP, I still want to know how wet years, dry years, and winds are outside of reasonable expectations in SoCal. These are part of the (stationary baseline) the paper should include. From a quick pass on the paper, it's not clear to me that the paper captures hysteresis due to intermittent wet/dry periods. Or that they considered any additive non-stationarity, in (stationary baseline + climate drift), they wouldn't deem anthropogenic.
Not denying here. Just enjoying throwing rocks at a paper adjacent to a past life. I have published on uncertainty quantification for computational fluid dynamics that employed explicit slow/fast timescale decompositions.
I live in the area affected by the Eaton Fire. I’ve been here for 10 years. We experienced severe droughts and wildfires in the first 8, and though they were bad fires and made the air feel like we were living in Bladerunner’s LA, it established a norm. In the winter we got used to seeing rains. 2 years ago at this time of year we had snowfall (!). Last year at this time we had hard rain. This year, same time, we have catastrophic wildfires that wipe out neighborhoods. I’ve never seen winds like the ones we saw. They were terrifying. Like being in a hurricane.
Anyway, that’s how I know it’s unusual…
Still, https://en.wikipedia.org/wiki/Santa_Ana_winds tells me
> "The strongest Santa Ana winds yet recorded occurred in early December 2011. An atmospheric set-up occurred that allowed the towns of Pasadena and Altadena in the San Gabriel Valley to get whipped by sustained winds at 97 mph (156 km/h), and gusts up to 167 mph."
The 2011 Citation 24 from that Wikipedia article, if one looks it up, includes the line
> "We haven’t had this kind of event in more than 10 years,” said Stuart Seto, a weather specialist for the National Weather Service in Oxnard, Calif. “This system is particularly special because there was cold air being pushed up, and it makes them even stronger. Some are going to be hurricane force, but all of it will be felt.”
So, roughly every 10 years there are hurricane force wind events in Greater LA out on the tail of the normal weather distribution. And documentation of those stretches over at least 20 years. And everyone interprets it as special at the time.
I quickly tried digging up historical Santa Ana data from peer-reviewed publications. The obvious article I found had data only back to the late 1960's and it was from 2003: https://journals.ametsoc.org/view/journals/eint/7/8/1087-356... I can't figure out if right now is a 1- or 2- or 3-sigma event when combined with changes in human living patterns and forest management patterns. That shouldn't change aid or the systemic response to helping the people involved. But it should inform how we collectively speak about these circumstances when they arise.
I grew up in an area that had awful flooding roughly every 30-40 years (e.g. https://en.wikipedia.org/wiki/Johnstown_Flood). It's presently overdue to happen again. That such disaster is infrequent doesn't change the humanitarian scope of the catastrophes when they happen, of course, but it does suggest that humans tend to discount the tails of historical weather patterns.