Science

The Next Threat to L.A.? Rainfall That Could Cause Landslides

Published

1 year ago

January 17, 2025

The Next Threat to L.A.? Rainfall That Could Cause Landslides

While winds and flames continued to ravage Los Angeles, small teams began creeping onto the charred soils left in their wake.

Roughly a dozen members of the California Watershed Emergency Response Teams and the United States Forest Service are studying the edges of the Eaton and Palisades fires to determine what patches of land burned most severely. Soon, they’ll issue hazard maps to help people prepare for what comes next: the near-certain threat of floods and landslides that will loom for days, months and even years while the city recovers.

“After a wildfire, the hazard to the public is not over,” said Jeremy Lancaster, California’s state geologist. He and his team spent Wednesday hiking in the steep canyons that flank the San Gabriel and Santa Monica Mountains. When it rains hard enough, the sediment on slopes like these can swiftly tumble downhill onto houses that increasingly push up against the fire-prone foothills.

The two major hazards after a wildfire are flash flooding and post-fire debris flows. While spongy soils typically absorb water, burned soils can become hard packed like concrete, repelling water as a raincoat would. Water then funnels downslope without much, or any, vegetation left after a fire to keep it in check.

Hazard maps use a combination of satellite images and field testing of soils to show where patches of moderately to severely burned soils could make these post-fire risks more likely. Recommendations for emergency services to engineer barricades against the danger accompany the maps.

The Palisades burn map was released on Thursday, and the Eaton map is still under review. Experts said the Palisades fire had mostly low to moderate burn severity, while the Eaton fire was likely to have more moderate to high burn severity.

Debris flows require three ingredients — steep slopes, burned soils and rain — and they’re often more dangerous than floods because the sediment they draw in claws at the landscape, creating a snowball effect that pulls a tumult of trees, vegetation, soil, rocks and anything else in its way.

“A debris flow is like a flood on steroids,” said Jason Kean, a research hydrologist with the United States Geological Survey. “It’s all bulked up with rocks and mud and trees.” While floods often have a longer reach, water churns faster in debris flows, which are less common but more destructive.

After the Thomas fire in 2017, a debris flow in Montecito, Calif., killed 23 people and damaged or destroyed more than 400 homes.

Neither homeowners’ insurance nor federal flood insurance covers the impact to properties of debris flows, which are defined by the Geologic Survey as landslides.

The fire-flood cycle is a long-studied relationship, but scientists say a warming planet has made the post-fire threat more likely. Fires burn bigger and more severely. Rains hit harder and more often. Those changes expand the target area for post-fire hazards, which could increase the size and the frequency of floods and flows.

“The fire scientists are telling us that wildfires are increasing in size and severity,” Dr. Kean said. “From that fact alone, you’re exposing more terrain and making more terrain vulnerable to post-fire problems.”

With a dangerous combination of very steep terrain, lots of sediment, high-fire activity and a lot of people pushed up against the mountains, Los Angeles faces an extreme risk.

“The Los Angeles area and Southern California are the world capital for post-fire debris flows,” Dr. Kean said.

Debris flows are so common in Los Angeles that at the edge of the San Gabriel Mountains, where the Eaton fire burned, the state has carved debris basins to collect waste from major flow events. In Southern California, more than two million people live on alluvial fans, landforms that are conducive to flash floods and debris flows, according to Dr. Lancaster.

The National Weather Service in Los Angeles collaborated with the Geological Survey to start the nation’s first early warning systems for these post-fire hazards in 2005. The geological survey sets a rainfall threshold that could set off landslides, and the Weather Service issues a warning if the rainfall they expect nears or surpasses it.

Jayme Laber, a senior hydrologist with the Los Angeles forecast office, has spent the last two decades issuing such warnings. While there’s still no sign of rain in the seven to 10 day forecast he issued on Wednesday, a garden-variety rainstorm that Angelenos see at least once or twice a year could be enough to kick off the next wave of hazards, which can develop within minutes.

“In a burned area, the kind of rain that would not cause problems would be a really light drizzly rain that just goes on and on,” Mr. Laber said. But at some point this winter, he added, “we’re going to get rainfall that has the potential to cause flash flooding and debris flows in these newly burned areas.”

This video of a small debris flow from 2016, which is close to the site of the current Eaton fire, shows how quickly large objects, like a six-foot boulder, can be sent rushing downhill.

Mr. Laber advised residents to prepare in case of a future evacuation, monitor the forecast and pay attention to local emergency officials if a warning is issued.

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Science

Bodies of all 9 skiers killed in devastating avalanche recovered by authorities

Published

1 day ago

February 22, 2026

Press Room

Bodies of all 9 skiers killed in devastating avalanche recovered by authorities

California search-and-rescue teams have recovered the bodies of all nine missing skiers killed Tuesday in a devastating avalanche in a remote region of Sierra Nevada north of Lake Tahoe.

When a catastrophic avalanche rumbled over a stretch of the High Sierra, dozens of law enforcement officers scoured the mountainside for a group of 15 skiers, including four mountain guides.

Within hours, crews rescued six survivors and discovered eight deceased skiers near the Frog Lake Backcountry Huts. Another skier was still missing, but was presumed dead.

After five days of navigating deep snowpack and treacherous weather conditions, authorities announced they had found the body of the ninth victim.

During a press conference on Saturday afternoon, Nevada County identified the victims as six skiers and three professional mountain guides:

Andrew Alissandratos, 34, of Verdi, Nev., a Blackbird Mountain Guide
Carrie Atkin, 46, of Soda Springs, Calif.
Nicole Choo, 42, of South Lake Tahoe, Calif., Blackbird Mountain Guide
Lizabeth Clabaugh, 52, of Boise, Idaho
Michael Henry, 30, from Soda Springs, Calif., a Blackbird Mountain Guide
Danielle Keatley, 44, of Soda Springs and Larkspur, Calif.
Kate Morse, 45, of Soda Springs and Tiburon, Calif.
Caroline Sekar, 45, of Soda Springs and San Francisco, Calif.
Katherine Vitt, 43, of Greenbrae, Calif.

Authorities lamented the fast-moving disaster as the deadliest avalanche in modern California history.

“There are no words that truly capture the significance of this loss and our hearts mourn alongside the families of those affected by this catastrophic event,” Nevada County Sheriff Shannan Moon said in a statement on Saturday. “The weight of this event is felt across many families, friends, and colleagues, and we stand together with them during this difficult time.” Moon said.

The avalanche occurred amid a powerful atmospheric river storm that unleashed several feet of snow onto the Sierra Nevada mountains. First responders maneuvered through the blizzard on snowcats and skis to rescue the survivors.

But the unstable snowpack, high winds and whiteout conditions made search-and-recovery efforts too perilous, prompting first responders to leave behind the bodies of deceased skiers and suspend operations on Wednesday and Thursday.

Authorities carved paths through the deep snow to eventually continue the search, and California Highway Patrol officers found the ninth victim.

The Nevada County Sheriff‘s Office was also assisted by California National Guard, California State Parks, Placer County Sheriff’s Office, Washoe County Sheriff’s Office, California Governor’s Office of Emergency Services, Truckee Police Department and the United States Forest Service.

Science

Video: ‘Very Successful Day’: NASA Completes Artemis II Launchpad Test

Published

2 days ago

February 20, 2026

Press Room

Video: ‘Very Successful Day’: NASA Completes Artemis II Launchpad Test

new video loaded: ‘Very Successful Day’: NASA Completes Artemis II Launchpad Test

transcript

‘Very Successful Day’: NASA Completes Artemis II Launchpad Test

NASA successfully completed a rehearsal to launch the Artemis II rocket on Thursday. The mission would send astronauts around the Moon’s orbit for the first time in more than 50 years.

: “Very successful day. I’m very proud of this team and all that they accomplished to get us to yesterday, and then to go execute with such precision.” “Following that successful wet dress yesterday, we’re now targeting March 6 as our earliest launch attempt. I am going to caveat that — I want to be open, transparent with all of you, that there is still pending work.”
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NASA successfully completed a rehearsal to launch the Artemis II rocket on Thursday. The mission would send astronauts around the Moon’s orbit for the first time in more than 50 years.

By Jorge Mitssunaga

February 20, 2026

Science

Fourth measles case confirmed in L.A. County; person visited LAX, restaurants while infectious

Published

4 days ago

February 19, 2026

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Fourth measles case confirmed in L.A. County; person visited LAX, restaurants while infectious

A fourth measles case has been confirmed in Los Angeles County, prompting renewed calls from health officials for residents to ensure they are protected against the highly contagious virus.

The infected individual flew from Singapore to Los Angeles International Airport on Feb. 9 aboard Singapore Airlines Flight 38. The plane landed at about 7 p.m. following a 14-hour journey, according to the L.A. County Department of Public Health.

Over the following days, the individual visited a few San Gabriel Valley fast food restaurants, potentially exposing others to the measles virus.

“As measles cases increase, it is important that residents take steps to make sure they are fully protected,” L.A. County Health Officer Dr. Muntu Davis said in a statement. “The [measles-mumps-rubella] vaccine is the safest and most reliable way to prevent measles and protect yourself, your family, and your community.”

The health department did not respond to questions from The Times regarding the sex or age of the infected individual, who was described in a statement as “a resident who recently traveled internationally.”

After arriving at and leaving the Tom Bradley International Terminal, the individual visited restaurants and convenience stores throughout Whittier and Montebello.

The individual ate at a Burger King in Montebello, 1212 West Beverly Blvd., on Feb. 10 between 5:30 and 7 p.m. The next day, the person dined at Taqueria El Atacor, 11156 1/2 Whittier Blvd. in Whittier, between 3 and 5 p.m.

The final two stops in Montebello were at Domino’s Pizza, 803 West Whittier Blvd., between 4 p.m. and 5:15 p.m. on Feb. 12; and 7-Eleven, 1106 West Beverly Blvd., on Feb. 13 between 4:30 p.m. and 5:45 p.m.

Those who were in the Bradley Terminal (Terminal B) on Feb. 9 from 7:30 p.m. to 9:40 p.m., or in the eateries above during the aforementioned time windows, may have been exposed to the measles virus.

Symptoms typically develop anywhere from seven to 21 days after exposure, according to the health department.

Concerned individuals should confirm whether they have protection against the virus, either through past measles vaccinations or infections.

Those who are not immunized or are unsure of their status should monitor themselves closely for signs of infection. Common symptoms include fever, cough, runny nose or red eyes, as well as a rash.

Those with such symptoms are encouraged to stay home and avoid school, work and any gatherings. They should also call a healthcare provider immediately, but not go into a healthcare facility without informing them.

The monitoring deadline for symptoms ranges from March 2 at LAX until March 6 at 7-Eleven for individuals who visited those spaces around the same time as the infected person.

Davis said the most effective way to protect against measles is to take the MMR vaccine. Children age 1 year and older are considered fully immunized after receiving two doses.

“Measles spreads easily and can lead to serious complications, including pneumonia, brain swelling, and even death,” Davis said. “We urge everyone to confirm their immunity and get the MMR vaccine if needed, especially before traveling. Taking this simple step helps safeguard your health and strengthens protection for our entire community.”

Previous cases confirmed in L.A. County so far this year also involved individuals who had traveled internationally. One of those individuals ventured to Sherman Oaks on Jan. 24, another to Woodland Hills on Jan. 30. The first case had no identified public exposure locations in L.A. County.

Measles cases have increased in the United States as vaccination rates have fallen in recent years, allowing the highly contagious virus to spread in communities with lower vaccine coverage.

According to the U.S. Centers for Disease Control and Prevention, there were 2,280 confirmed measles cases in the U.S. last year, the highest annual total since 1991. As of Feb. 12, 910 cases had already been confirmed nationwide this year — including 15 in California.