Flooding in California: What Went Mistaken, and What Comes Next
California’s precipitation forecast for December 26 to January 11. Source: Weather Prediction Center
Battered by storm after storm, California is facing intense flooding, with at the very least 19 lives lost thus far and nearly 100,000 people evacuated from their homes. And there’s no sign that the storms will likely be letting up soon.
Below, experts from across the Columbia Climate School help to elucidate this devastating weather and what it means within the broader conversation of climate change and disaster response.
Unusual, but not unheard of
“The floods are as a consequence of recurrent waves of atmospheric rivers that typically result in very high rainfall. These should not unusual for California,” said Upmanu Lall, an engineering professor and director of the Columbia Water Center. Atmospheric rivers are air currents that carry large amounts of water vapor through the sky.
Modeling by the U.S. Geological Survey predicted a devastating scenario like we’re seeing now, Lall said. The projections were based on the storms that caused disastrous floods in California in 1861-62.
“There may be sedimentary evidence from a UC Santa Barbara study that such a phenomenon recurs in California about every 250 years,” Lall added.
El Niño/La Niña effects
El Niño and La Niña — climate patterns within the Pacific Ocean — can influence where atmospheric rivers make landfall, and the way incessantly, said Lall.
He explained that atmospheric rivers are born in the nice and cozy waters of the tropical Pacific. Through the La Niña phase, atmospheric rivers will typically be born within the western Pacific and make landfall on the northern a part of the U.S. West Coast. Conversely, during an El Niño phase, atmospheric rivers usually tend to be born within the central or eastern Pacific, and make landfall in Southern and Central California.
“Because the Pacific transitions from La Niña to El Niño, which could also be happening now, the birth locations and the landfall locations can shift to intermediate locations and one typically gets this sequence of events that may cover different parts of California,” said Lall. “The rationale that is critical for flooding is that we get several such storms spaced a couple of days other than similar birth locations.”
Downed trees and flooding in Folsom, California, on January 9. Photo: FolsomNatural
Forecasts vs. preparation
The US Geological Survey modeling and past disasters made it clear that one of these weather was possible, and that local agencies must be prepared.
As well as, “Starting last month, the US government agencies began issuing forecasts that indicated the upcoming possibility of something like this happening within the immediate term,” said Lall. He suspects that this information did help to stop some damage — for instance, with reservoir operators taking motion to stop dams from overflowing or bursting.
And the forecasts were pretty good when it comes to providing a way of when and where to expect heavy rainfall, said Andrew Kruczkiewicz, a senior staff associate on the Columbia Climate School’s International Research Institute for Climate and Society. So why are people dying?
It comes all the way down to a niche between science and decision-making, said Kruczkiewicz. “How can we translate the forecasts of the heavy precipitation into an actionable form? How can we tie in standard operating procedures before a disaster occurs, understanding that the forecasts aren’t perfect, but making it in order that motion could be taken? And even when there are systems which are designed for the forecast to guide to specific actions, are we sure that probably the most underserved populations are receiving the message and are in a position to take motion?”
He said that outdated governance structures should not designed to show forecasts into motion, especially now that the climate and social contexts around disasters are changing over time.
“We could have done higher given the forecast information we had available. But without the interpretation into motion, the potential value of ‘skillful’ forecasts goes untapped or under-utilized.”
Jeffrey Schlegelmilch, director of the Columbia Climate School’s National Center for Disaster Preparedness, echoed the necessity to work on turning forecasts into motion. He said that it’s easy to research disaster response looking back. “But how can we higher utilize the info we’ve got prospectively when it looks just a little different from the hazards we normally face? That’s among the many questions emergency managers and elected officials must be enthusiastic about, along with the entire broader infrastructure and impact issues.”
Communication breakdown
Kruczkiewicz thinks that a part of the rationale people weren’t higher prepared for these storms is due to poor communication. He said that while the term “atmospheric river” could also be attention-grabbing, it’s a dangerous oversimplification. Greater than rain and flooding, atmospheric rivers can bring high winds, blizzard conditions, mudflows, and rockslides.
“There’s no atmospheric river preparedness motion,” he said. As a substitute, he thinks Californians would have benefited and lives could have been saved by understanding which hazards are specific to different locations.
“I believe sometimes these terms [like atmospheric river], yeah, they’ll get clicks, and to some extent raise awareness,” said Kruczkiewicz, “but they do cause confusion. And in a disaster situation, confusion means time, and time means potentially increased impact. And frequently what we see when we’ve got that sort of delay and increased impact is a prioritization of the more wealthy populations and form of a de-prioritization of the lower income and traditionally underserved.”
Kruczkiewicz thinks the media is missing a chance to spotlight how underserved communities are disproportionately impacted by events like this. The wealthy and powerful may experience disruptions, but overall they’ll weather the storm or move if needed, whereas individuals with less money and privilege have fewer options to guard themselves from and bounce back after a disaster.
“Lower income populations could have their homes destroyed, and/or could also be forced to miss weeks of labor, and/or can experience physical and mental injury that requires medical care that they’ll’t afford,” he said. “Most of these impacts could also be significantly longer lasting than the impacts in wealthier areas and in areas of upper economic activity.”
Complicating aspects
For greater than twenty years, the Southwest has been in a severe megadrought. It’s possible that these dry conditions contributed to California’s deadly floods, said Kai Kornhuber, an adjunct associate research scientist at Columbia Climate School’s Lamont-Doherty Earth Observatory.
“If you have got very dry soil and it’s raining, then in fact the water can’t be absorbed as quickly, and frequently that amplifies flooding,” he explained. “To what degree this plays a job here must be assessed regionally.”
Moreover, wildfires exacerbated by the drought could possibly worsen the impacts of the storms, said Kornhuber. By removing trees and abandoning exposed soil, wildfires are known to increase the chance of landslides. Nonetheless, he cautioned, “this may be very early, so there’s no data — there’s plenty of speculation in the meanwhile.”
Whither the drought
Could the atmospheric river conditions help to treatment California’s drought conditions?
“Actually there will likely be some locations within the West that can have improved water conditions for this reason atmospheric river event,” said Kruczkiewicz. “There will likely be some areas that get an appropriate amount of rainfall, or an above average amount of rainfall that’s distributed in time, well enough for them to handle that rainfall. So in some areas there could also be some overall advantages.”
Nonetheless, many areas that need water won’t see a profit because they’re not in a position to absorb the quantity of water that’s raining down, and the negative impacts of mudflows, landslides, and flash floods will far outweigh any positive impacts, he said.
Some areas are receiving heavy snowfall, which may gain advantage the water supply over the long run; during warmer months, melting snowpack and ice helps to replenish depleted streams and aquifers.
“But what are the prices that we pay within the short term when it comes to socioeconomic impact, when it comes to lack of life, when it comes to infrastructure damage?” asks Kruczkiewicz.
Climate change’s role
What role did climate change play on this seemingly limitless parade of storms marching across California?
“Extreme precipitation is getting more frequent with warmer climate in lots of regions globally,” said Kornhuber. “A recent study suggests that climate change is increasing the frequency and magnitude of such storm sequences that impact California.”
Nonetheless, he said, with atmospheric rivers on the whole, “it’s a bit difficult to say to what degree climate change is altering their frequency,” partially since it’s not clear how atmospheric circulation will change because the climate continues to warm.
A flooded walnut orchard in Chico, California. Photo: Frank Schulenburg
Seeking to the longer term
Researchers on the Columbia Climate School are working to higher understand climate phenomena like we’re seeing in California, and to translate the info into real-world motion and adaptation.
Kruczkiewicz said that when more data about this disaster becomes available, he plans to have a look at where flash floods are happening. There are lots of areas experiencing these sudden floods brought on by heavy downpours for the primary time ever, and he wants to know those trends with the intention to higher communicate risk and inform government policies.
Lall and his colleagues on the Columbia Water Center are exploring whether or not they could actually steer atmospheric rivers by nudging them with small amounts of energy.
“The fundamental idea is that the system is chaotic, i.e., it is extremely sensitive to small perturbations, so if we nudge it at just the correct time and place then the last word landfall location may very well be modified significantly,” said Lall. “If successful, one could steer an atmospheric river away from a spot that’s prone to be flooded to a spot that’s in drought. Thus far, we’ve got explored this concept mathematically, in an idealized model and established its plausibility. Research on the way it could actually be done is an open query. If this is feasible, then we open a latest chapter for adaptation with significant reduction in flooding and drought impacts, and proactive management of water futures.”
One major takeaway from this disaster is that climate impacts have gotten increasingly common and increasingly complicated, piling on top of one another in each time and space — and disaster resilience, preparedness, and response must adapt accordingly.
“Planning for extreme events must be the norm,” said Schlegelmilch. “How we construct our towns and cities and the underlying infrastructure all has so much to do with how bad the impacts will likely be. So we’d like some rethinking on the worth of more resilient buildings within the face of a changing climate, and the way equity plays into the unevenness of disaster vulnerability and recovery.”
