The Brief

Researchers out of UC Irvine have said that nationally used flood modeling lacks specificity when it comes to measuring risks in urban areas like Los Angeles County.

They've created their own modeling system, PRIMo-Drain, that can better predict which properties are at risk when using accurate, granular data.

How the flood modeling system works

In a new report, UCI engineering professor Brett Sanders and his team compared widely used national flood risk assessment modeling in areas like Los Angeles County against their own PRIMo-Drain model. Long story short: Traditional models don’t usually include infrastructure like levees and dams, unresolved drainage and topographic data, which means their modeling is less specific when it comes to measuring risks for the spreading of floods in cities.

That data on storm drain infrastructures is collected mostly from GIS (geographic information system) shape files maintained by public agencies like the Los Angeles Department of Public Works. The UCI researchers also updated those databases with aerial image capture of the conditions of levees mapped in public records.

“Once we have this relatively detailed representation of the land surface, of the flood infrastructure, we look at different types of flooding,” Sanders said.

Those types of flooding include river floods, coastal floods, and flash floods from intense rainfall, like what Los Angeles saw the past two winters. Estimates show the frequency of extreme rainfall under a warmer atmosphere to likely be higher in seasons to come.

In recent years, large rainfall events in Southern California have been kept at bay by flood control infrastructure like those aforementioned levees and dams (the technical word for them is mainstem). But water is starting to reach above levee and dam walls more often. Places like Santa Barbara and San Diego experienced these flooding scenarios in the latest few rounds of atmospheric rivers.

This is why PRIMo-Drain researchers want to get as specific as possible in future models. If they could measure where water goes after escaping flood control walls and what areas get flooded, even more accurate models could be put to use for cities.

According to Sanders, part of this is why the developers of the model engage in “collaborative flood modeling” with the Los Angeles Regional Collaborative for Climate Action and Sustainability out of UCLA. The idea is to ask people where they see flooding, what they think drives flooding, and for suggestions on data sources that could help improve the model.

The model became publicly available in 2023. Since then, organizations like the City of Los Angeles and Southern California Edison have used PRIMo for planning and vulnerability measurement purposes.

Strategies to maintain flood risk

Right now Sanders and researchers on the PRIMo team are engaged in a two year study in Los Angeles in partnership with Los Angeles County and community groups to look at alternative strategies to manage this risk to communities and who they would benefit. (The same team also conducted a 2022 study that found L.A. County’s Black residents face disproportionately high flood risks.)

There are three strategies they’ve identified as potential solutions. The first is a tried and true method: make levees taller so that channels have more capacity and can prevent water from escaping the levee walls.

Another strategy involves widening channels to create more capacity, which would eliminate some of the concrete in channels and allow for vegetation to begin growing.

Sanders said the third strategy would be to “capture more storm water in the upper parts of the watershed…with more parks, more green space, and more infrastructure that would promote the infiltration of rainwater into the soil.” Ideally, this would reduce the amount of water that flows down these channels and in doing so reduce the risk facing these lowland cities.

In the meantime, the researchers will continue working on updating their models during future rain events. According to Sanders, it’s still “really hard to say [the researchers’] method is more accurate” since it hasn’t been exposed to enough severe flooding.

In a cozy dance studio in Garden Grove, dancers of all experience levels, ages and backgrounds flock to Queer Latin Dance OC to learn the steps to salsa, cumbia and bachata.

For many, the dance class is more than educational — it’s a place to get away from it all, to find community and to uplift one another through art.

When Rodrigo Marquez founded Queer Latin Dance OC at the beginning of this year, he said he was filling a gap in Orange County that often lacks safe spaces for the LGBTQ+ community.

“I wanted to make creative communities for us to learn in a safe environment,” Marquez said. “Everyone's here to learn, and I want the pressure of whatever's going on in the world, just to forget for the next hour.”

Queer Latin Dance OC meets three times a week to learn the steps to salsa, cumbia and bachata.

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Destiny Torres

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LAist

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What are the dance lessons like? 

When creating his teaching plan, Marquez said he considers the range of experience his students might have. Everybody starts somewhere, he added, and the hardest part is showing up.

“It is scary, but if you're already showing up, then just jump in and just forget about the world. It's a great distraction, and dancing makes you feel better,” Marquez said.

Philip Lee, an elementary school teacher from Tustin, took his first class with the group Monday night, trying the quick steps of salsa.

“I had a stressful day. … All my stress that I had in my neck and upper back just kind of went away,” Lee said, adding that the high energy in the room is infectious. “It was nice just laughing with people in the community and meeting new people.”

Lee said the dance lesson gave him a space to be with community.

“The queer community specifically, and just kind of let my guard down and just be free and laugh and enjoy being me and celebrated for a love for the arts,” Lee said. “That's not a space that is always safe.”

Before taking lessons at Queer Latin Dance OC, Melba Rivera said she came in with zero dance experience.

“You come as you are. No matter what level you're at or how you identify or what your experience is, everybody's here and everybody's learning,” Rivera said. “It's a very encouraging and motivating space.”

Salsa and bachata are social dances, Marquez said, but one thing that makes his class unique to many is that regardless of gender identity, anyone can follow or lead.

Typically, the lead falls to the male dancer, and women follow. Marquez said it was important that no one feels pressured to be one or the other.

“That's why I created this, so people like me can just come and learn, not be expected to be in a gender role based on how they look,” Marquez said. “They want to dance how they feel.”

Why it matters

Taryn Heiner said, especially in Orange County, it’s challenging to find spaces that are queer-friendly and queer-open.

“That's really what makes this space so kind and warm and welcoming,” Heiner said. “We have all that base understanding of respecting one another, no matter who they are, who they love and what they do.”

Growing up in Orange County, not every room you walk into is a safe space, Rivera added.

“So walking into a room like this, where everybody's friendly, everybody's learning, everybody's just here for the same purpose to get better, to support each other, is really important,” Rivera said. “Not just in the class, but [in] the friendships we make outside of the classroom.”

Outside of dance class, Marquez’s students meet up for monthly hikes and other get-togethers. Marquez said it is a privilege and an honor to bring people together through his love for dance.

“I've seen people become friends since January, and I see them practice outside of practice,” Marquez said. “I've always had a dream to do my own dance classes, but to do it in a way where people can connect and just be themselves. It's far greater than that.”

Queer Latin Dance OC offers lessons to dancers of all experience levels and has created a new community hub in Orange County.

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Destiny Torres

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LAist

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Want to dance? 

Salsa, cumbia and bachata classes are held three nights a week on Mondays, Tuesdays and Thursdays. Classes are $20 per session, but Marquez also offers a free beginner salsa class every Monday.

You can register for the class of your choice here. Payments are taken in person.

Border Patrol agents have been roving from city to city over the last 15 months, far from their home bases in California and elsewhere along the U.S.-Mexico border, engaged in an unprecedented mass deportation campaign.

A collaboration between CalMatters, Evident Media and Bellingcat has tracked these agents, documenting their tactics on the ground and through mountains of video footage, since their first proof-of-concept raid in Bakersfield in January 2025.

Exactly one year later, an Immigration and Customs Enforcement agent shot and killed Renée Good in Minneapolis, followed weeks later by the killing of Alex Pretti by a Border Patrol agent.

Our investigation shows that beyond those two shootings, immigration agents engaged in a pattern of force and questionable detention, aggressive tactics that courts have said likely violated the Constitution, as they moved from Bakersfield to Los Angeles, and then Chicago and Minneapolis.

In each city, federal courts stepped in to restrain them from violating civil liberties in that jurisdiction. Agents later deployed to another city. The video evidence suggests agents’ tactics became more brazen with each stop.

Under President Donald Trump, immigration agents have operated without typical public accountability. Many agents wear masks. Incident reports are largely hidden from the public.

“We are in a completely uncharted world now with these masked agents,” said John Roth, who served as inspector general of the Department of Homeland Security under Presidents Barack Obama and Trump.

“The first thing that you do when you give an agent a gun and a badge and the authority over American people is to make sure that they follow the Constitution, period,” he said.

In this new film, we focus on the activity of five agents from the US-Mexico border whose identities we’ve been able to confirm.

Watch the documentary

We are not aware of any disciplinary action taken against these agents. DHS did not respond to requests for comment; the individual agents either declined to comment or didn’t respond to calls or emails.

We showed the incidents to Roth and Steve Bunnell, former DHS general counsel. Both have testified before Congress, raising the alarm about what they see as a dismantling of the department’s accountability and credibility. Roth called the incidents “difficult to watch.”

“There are sort of two essential components of DHS and law enforcement generally being effective, and that’s trust and credibility,” Bunnell said. “And they have lost those things to the extent they had them.”