LA Wildfires - The Unforeseen Dangers of Compound Weather Events
With the city of Los Angeles currently in a state of chaos as devastating wildfires continue to spread across the region, authorities and emergency services are struggling to keep it contained. With this, many are questioning the factors that led to such a record-breaking event.
On January 7, just as we had ushered in the new year, a series of wildfires broke out across the city of Los Angeles, California. Reaching a height of 5 fires burning simultaneously, over the following days the conflagrations devoured tens of thousands of acres of land, consuming tracts of forest and countless houses. Already, this is looking to be one of the most damaging and costly natural disasters in the history of the United States.
The largest of the fires, the Palisades wildfire, has ravaged through over 23,000 acres and, as of yet, is only 14% contained.
As these fires continue to rage unabated, with economic costs mounting - some estimate that total damages could exceed $150bn - and the death toll rising each day, people are rightly questioning both why the fires were triggered in the first place and how they have been allowed to spread so far out of control.
Initial Embers
In terms of what caused the first spark of a fire, investigators are currently uncertain. The leading cause of wildfires across California, which has been the trigger in most previous instances, is lightning; the regularly dry conditions found across the state’s landscape, in combination with frequent bouts of stormy weather, makes for a tinderbox situation.
However, investigators have already been able to rule that out as a potential cause - there had been no reports of lightning strikes in the vicinity before the wildfires took hold.
This leaves two other potential options: arson or electrical fire. Scant evidence exists for the first theory, despite it having made a splash in the headlines; this week, a man was caught with a blowtorch, reportedly trying to start a fire in the neighbourhood, before he was confronted by the local residents and restrained until the police could arrive. More likely is this was related to an electrical fault.
Yet, whilst identifying the underlying cause will unlock a crucial part of this story, and ultimately contribute to preventing this from happening again, what is rightly garnering more attention are the climatic factors that led to not simply the fire igniting, yet spreading to the extent and the velocity that it has.
Out of Season
One of the more striking features of this fire is the time of year when it struck: simply put, January is not wildfire season in California. However, it seems that as the climate warms and major weather events become more unpredictable, these more ‘out-of-season’ phenomena may become more commonplace.
California governor, Gavin Newsom, stated recently that there is now “no fire season” and that we can expect to see these types of events recurring “year-round”.
But what is it specifically about the changing climate that led to such a devastating event? It would seem that a whole panoply of factors were involved, both during the period when the blazes were starting and leading up to the event.
California has long been known to suffer from extreme droughts and, up until recently, had experienced one so prolonged that it extended into decades. This, to the relief of local residents, came to an end in 2022 and was followed by a period of rainfall that allowed the region to rejuvenate, particularly in terms of plant life and vegetation.
Then, the level of precipitation yet again went through a 180° shift, falling again to record lows; over the past few months, only 0.16 inches of precipitation has fallen over the region, approximately 4 inches below what would otherwise be expected for this time of year. This has meant that the vegetation that boomed back in 2022 has now become dried and desiccated, forming the perfect kindling should there be any initial spark.
Some have described such phenomena as “whiplash” events, whereby there is a marked transition between very wet and very dry conditions that provides exactly the kind of fuel the spreading flames need. According to a recent study published in the journal Nature, levels of such hydroclimate volatility have risen by 31-66% since mid-century as a result of climate change, with it expected to rise even further in frequency as the climate continues to warm.
One concept that has relatively recently entered the suite of climate change jargon has been “compound weather events”, whereby coinciding extreme weather events stack to create conditions that are even more damaging to human life, society, and the environment than any that struck in independence. What this study demonstrates, with the LA wildfires as a very tangible real-world example, is that these weather events must also be analysed with a consideration of sequential events. This means that the cumulative effect on the landscape as a result of multiple weather events striking over a period of time can have an augmentative impact on the effects of each. In this instance, it has not just been high precipitation followed by a period of drought, but this has been exacerbated by unusually high wind speeds.
Fanning the Flames
The Santa Ana winds are an incredibly common weather event in this part of the United States, striking up to 20 times over a year. They are very strong north-easterly winds that blow from inland out to the coast and form when a high-pressure system sits in the region north and west of California, namely much of Nevada and other nearby states. As winds flow clockwise around these high-pressure systems, they flow down through into California, where it begins to descend as it reaches the coast. This process causes the wind to speed up, which further accelerates as it becomes funnelled through the valleys and mountains in the region.
As it descends, the air moisture saturation also drops. Given that these winds have blown in from states like Nevada, notoriously lacking in moisture, these winds are incredibly dry by the time they hit cities like LA.
Their contribution to these recent wildfires has likely been one of the most important factors. The Santa Ana winds of this month have been relatively strong, reaching approximately 70mph at points. What this meant for the local area was that these fast, dry winds blowing across the landscape acted much as a hair dryer would, sucking moisture from the land and reinforcing the effects of the previous drought. On top of this, the winds were such to push the flames further across the landscape, contributing to their rapid spread; in recent weeks, firefighters have warned that the return of Santa Ana winds would be one of the greatest challenges they face in containing the fires.
This serves to underscore just how damaging compound weather events can be.
A Deteriorating Housing Crisis
Evidently, wildfires can be incredibly damaging natural phenomena, made even more impactful by the effects of human-caused climate change. On the face of it, the sheer area of land that has been reduced to ashes, including property and vegetation alike, and the individuals who tragically passed away as a result of the flames are the most clear-cut impacts of this recent spate of wildfires. However, analysts are already starting to estimate the long-term costs to LA society, many in ways that might not immediately be obvious.
Possibly one that will have greater ramifications for a city like LA is its impact on the homeless population. According to estimates from 2024, there are an estimated 45,000 homeless individuals in LA, 29,000 of whom are unsheltered. As the recent wildfires have claimed an estimated 12,000 structures in total, many thousands more are likely to be made homeless as a result, unless public intervention can safeguard residents against this. However, with the California FAIR plan, the public housing insurance provider, potentially with insufficient funds to pay out the claims of all residents, it is possible that this safety net might not be strong enough.
This recent spate of wildfires is also having a uniquely troublesome impact on LA’s homeless population, highlighting just how much more vulnerable certain groups in society are than others. For instance, groups such as the Sidewalk Project and Union Station, providers of service for the city’s homeless population, are facing a number of challenges with regards to continuing to provide housing to those without; thus far, a series of housing facilities have been damaged by the wildfires, with many having to be evacuated. There is also growing concern amongst these groups for how their organisations can adapt or expand to meet what they expect to be a surge in demand as a result of the wildfires.
In particular, these wildfires have also demonstrated how emergency responses to disasters can often mean certain populations fall through the cracks and are not considered as fully as they should be. We have seen that mandatory evacuation orders, in the regions where they were implemented, were delivered almost exclusively through emergency alerts, namely on smartphones. As many in the homeless population do not have access to these, this message was not communicated to them and they were very much left behind, further endangering an already vulnerable demographic.
In the long term, it is expected that the effects of these wildfires and the sheer extent of the damage will contribute to a further deterioration in the city’s housing crisis.
As often happens during periods of disaster, there are certain opportunists looking to exploit the situation for their own gain, often financial. In the past few weeks, we are already starting to see evidence of this with relation to housing - reports are emerging of price gouging amongst landlords, hiking up rents for their tenants, as a result of the housing stock having become further constrained. Despite price gouging being a crime under state and federal law, this has not stopped some landlords from looking for a quick buck.
If these wildfires were to fundamentally alter the state of the LA housing market, the results could be immense. For example, the homeless population could go through a renewed surge, and the changes to housing and rental rates could easily price out a number of residents. We could very easily envision a reality where the economic costs of climate change start creating climate refugees, causing an exodus to regions with cheaper prices.
This is just one example of a growing climate reality that would have been inconceivable only a few decades ago. Now, these events have become part of our lived reality.
Over recent years, as global temperatures continue to surge, we have seen a growth in not only the intensity of individual climatic events - rainfall, drought, heatwaves - but in their coinciding occurrence, leading to much more lethal and damaging events than if they were to each strike independently.
And with this sheer uptick in intensity, we are starting to see effects, both immediate and in the longer term, that will have ramifications across society for years to come.
Before the Storm
In the latest developments, a new fire has firmly taken hold approximately 45 miles (72 km) north of the city of Los Angeles. Again, as with the previous fires, the Hughes fire quickly spread across the parched landscape, swelling to a size of 10,000 acres in the space of just a few hours on the morning of 22 January, again fuelled by the tinder-like conditions.
About 31,000 in the local area underwent mandatory evacuation, with another 23,000 having been warned that they may yet need to leave.
Fortunately, the impacted region surrounding Lake Castaic, a popular recreation area, is not nearly as densely populated as the major conurbation to the south. Thus far, there have been no reports of homes or other structures being burned in the vicinity.
However, whilst the threat of further fires had always been an ever-present possibility, a growing concern is, surprisingly, the potential that this weekend could bring some of the heaviest rains so far this year.
Whilst only anticipated to see less than 1 inch of rain over the entirety of the weekend, this brings with it some very particular risks. First and foremost, despite the expected rains the region is still seeing drought-like conditions, which means that the potential for any lightning during the incoming storms could cause further wildfires to start.
Yet the major risk is that, with the recent fires having stripped the ground bare of any protective vegetation and reduced a number of structures to ash, the top layer of sediment and any rubble and debris left behind could become swept up in the upcoming deluge. As was seen back in 2018 in the town of Montecito, a town around 80 miles (130 km) north-west of LA, which suffered through extensive mudslides after rain hit the nearby mountains, themselves stripped bare due to recent wildfires, LA itself could experience a similar event, but potentially on a larger scale.
In preparation, Los Angeles Mayor Karen Bass issued an executive order to enforce the cleanup of debris and fire-related pollutants, including removing vegetation, reinforce hillsides and roads to prevent the flow of mudslides, and install reinforced concrete barriers and sandbags at strategic points across the city.
On top of this, there are concerns that the pollution left behind by the destruction of property could potentially be toxic to inhabitants, particularly if it were to mix with rainwater and spread over a wider area. In particular, such pollution often contains heavy metals, which can cause skin irritation and sickness.
This just serves to underscore yet another example, in seemingly just one natural disaster, of the threats posed by sequential and compound weather events.
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