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California Storms

Starting in late December 2022, Californians suffered through historic levels of rain and snow that flooded roads and homes, forced evacuations and cut power to millions.

Almost the entire state received 400% to 600% of its typical average rainfall between Christmas 2022 and mid-January 2023. From late December 2022 through early April 2023, California endured at least 12 atmospheric river storms, corridors of air that can carry massive amounts of water over thousands of miles, producing cascading impacts including landslides, sinkholes and downed trees that damaged roads and homes.

On March 21, a bomb cyclone brought a destructive combination of tornadoes, wind gusts, heavy rain, flash flooding and mountain snow. “Bomb cyclone” is a term used to describe bombogenesis, a storm (low-pressure area) that undergoes rapid strengthening. A second bomb cyclone in two weeks brought more precipitation to the state the week of March 27.

A winter storm in late February 2023 produced feet of snow across the state, trapping people in their homes and vehicles and leading to dozens of rescues. California’s Office of Emergency Services deployed the California National Guard to help dig out snowbound communities in the mountains.

Rain and snow battered large parts of California once again on March 10, resulting in the deaths of at least two people, according to California Office of Emergency Services Director Nancy Ward. The storm brought significant snow totals to communities in the Sierra Nevada range, leaving thousands of households without power for essential light and heat.

The repeated events accumulated on one another and worsened disaster impacts while also impeding recovery efforts. While clearing debris, providing shelter and supporting other immediate needs were important, philanthropy should consider longer-term recovery needs and how to strengthen resilience.

(Photo: Major storm damage on a state highway in California, Jan. 14. 2023. Source: Caltrans District 7)

According to Philanthropy California, “As California continues to experience these repeated hazard events, it is not sustainable, nor realistic, to expect philanthropy to support individual, isolated disaster that occurs across California at the scale needed for a resilient recovery. We must instead center building community resilience as the highest priority for disaster philanthropy.”

Burn scars in Southern California are at risk of dangerous debris flows. Evacuation orders were given to residents in Santa Barbara County residing near the Alisal or Cave burn scars ahead of the March 13 storm. Experts worry California’s wintertime rain and snow could prepare the landscape for an intense wildfire season. A lot of moisture can increase the amount of spring growth, and when the growth dries out after limited additional moisture, it becomes an additional fuel source. The ingredients for a dangerous fire year were slowly coming together.

An additional threat is spring flooding. The National Oceanic and Atmospheric Administration says spring floods are possible across much of California’s coast. According to the California Department of Conservation, “When heavy rainfall stops, the risk of deep-seated landslides begin–when water percolates deeper under the surface to saturate weak zones of rock.”

Research published in January in the journal Nature Climate Change shows that the wettest and most extreme winter storms in the western U.S. are only growing wetter and larger. In a warmer world, these powerful storms are spreading to drench more land while simultaneously growing more intense at their cores.

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Key facts
  • The series of winter storms in late December 2022 through mid-January 2023 caused at least 22 storm-related deaths across California, which is more lives lost than wildfires in the past two years combined. Storms in early March resulted in the deaths of at least two people. On March 9, the San Bernardino County Sheriff’s Office said it had responded to 13 death investigations, but it was unclear how many lives had been lost due to various blizzard-related factors including downed power lines and blocked roads preventing people from accessing critical medical care. At least five people were killed when a bomb cyclone hit California on March 21.
  • The California Geological Survey (CGS) said they had counted more than 700 landslides across the state between Dec. 30, 2022 and Jan. 23, 2023. CGS said, “Large, deep-seated landslides can happen weeks to months after heavy rains and remain a hazard through the spring and summer.”
  • The National Weather Service (NWS) declared a “high risk” of excessive rainfall in both coastal and mountainous zones in California the week of March 13. The NWS only makes such proclamations about 15 times a year across the U.S., but they are associated with 80% of flood losses.
  • The storms through January 2023 helped the Sierra Nevada region to reach more than 200% of its typical snowpack for that time of year, which eased immediate drought concerns. By March, many areas in the Sierra had already surpassed 600 inches of snowfall, and statewide the snowpack improved to 212% of normal.
  • According to the National Weather Service Weather Prediction Center, the statewide average rainfall for California between Dec. 26 and Jan. 17 was 11.47 inches.
  • Precipitation totals broke records including in San Francisco, which on Jan. 4 marked the wettest 10-day period since January 1862.
  • AccuWeather said on March 14: “There is now about 5 times the historical average of water locked up in the snow cover in the southern Sierra, more than double the average in the central Sierra and 1.6 times the average across the north.”
  • Data from the California Department of Water Resources indicates that the state’s snowpack total for 2022-23 likely surpassed the record set 40 years ago in 1982-83. While the news was welcome in drought-ridden California, it does come with flooding risk.
  • Following weeks of rain and snow, short-term drought conditions and reservoir levels improved, but California is not in the clear when it comes to long-term drought. By early March the amount of water in the snowpack was expected to continue to alleviate leftover drought conditions but also contribute to ongoing flooding.
  • Estimates from Moody’s put the total U.S. economic losses from the California flooding and severe weather in late December 2022 through mid-January 2023 at $5 billion to $7 billion. The flood’s damage highlighted the need to address infrastructure, which requires significant resources.
  • The storms and damages from subsequent flooding resulted in the disaster becoming one of the first of 2023 to be included in the National Centers for Environmental Information’s list of billion-dollar disasters.

A spokesperson for the Governor’s Office of Emergency Services said on Jan. 17 that the number of houses and other structures that will be red-tagged as uninhabitable could be in the “low thousands.”

A challenge for homeowners when it comes to recovery and reconstruction is the fact that very few homes in California are protected by flood insurance. According to Moody’s, less than 2% of California households have flood insurance.

Following this series of disasters, the presence of mud and debris in homes is a significant health and safety concern and prevented people from getting back into their homes.

Residents and business owners in Northern California were victims to “snow loading” which occurs when rain weighs down on snow already settled on a roof, potentially causing collapse.

Santa Cruz County spokesman Jason Hoppin said the storm damaged 131 homes in the county. At least one home was buried by a landslide in remote Matilija Canyon, near the town of Ojai. The canyon creek flooded and the surrounding hills, which were stripped of vegetation in the 2017 Thomas Fire, began to sweep down. Officials in Calaveras County red-tagged 20 homes for being inhabitable due to storm damage.

In San Joaquin County, 175 residents of a mobile housing park were evacuated on Jan. 15 due to flooding. Mobile home residents have higher exposure to natural hazards such as wind and tornadoes, hurricanes, extreme heat, wildfires and flooding compared to those who live in other types of housing. On Oct. 12, CDP hosted a webinar about the increased risks manufactured homes face and the role they play in disaster recovery.

Public infrastructure

Significant damages were reported across the state to roads, bridges, water facilities, public buildings and equipment. According to Monterey County officials, the county suffered at least $30 million in public infrastructure damage during the early 2023 storms. In Sonoma County, officials estimated that storm system caused about $11 million in initial damage to local roads and other public infrastructure.

Damages to public infrastructure can have knock-on effects including blocking access to isolated or rural communities. The heavy precipitation resulted in dramatic images of sinkholes which occur when collected water weakens the ground supporting the surface above, making it more prone to collapse.

On March 12, residents in Monterrey County were forced to evacuate after the Pajaro River’s levee was breached by flooding from the latest atmospheric river to pummel the state. The evacuation orders applied to around 1,700 residents from the unincorporated community of Pajaro, many of them Latino farmworkers. A state law passed last year provided state funds for a levee project, which was scheduled to start construction in 2024. For decades, government officials have known that the levee was vulnerable “yet never prioritized repairs largely because their cost-benefit analysis didn’t value the losses of a low-income town.”

Investments in infrastructure aimed to provide relief to California, which has been stuck in drought for decades, paid off as millions of gallons of rainwater fell across the state. Rainwater captured by cisterns, catches, wells and underground basins represent gradual and not insignificant progress on the goal of improving the collection of rainwater.


By mid-January, the storms had helped the Sierra Nevada region reach more than 200% of its typical snowpack for that time of year, which eased immediate drought concerns.

By March, many areas in the Sierra surpassed 600 inches of snowfall and the snowpack in California has improved to 212% of normal. Regarding total surface water availability, the short-term recent drought is essentially over but the long-term drought remains due to groundwater deficits.

Although the drought monitor as of May 11 (see image below) showed improvement, much of California remains in some sort of drought or abnormally dry conditions. The state would likely need to have many wet winters to make significant gains in groundwater storage.

Source: U.S. Drought Monitor

“The water issues haven’t gone away,” said Jay Lund, vice director of the Center for Watershed Sciences at the University of California, Davis, “they’re just taking more of a backseat.”

The abundance of snow and rainfall could also lead to spring flooding as the snow melts. After years without enough water, officials have been forced to take drastic measures like releasing excess water from reservoirs. With much of the storm’s runoff ending up in the ocean, there is renewed interest in capturing rainfall for dry times.

Marginalized and at-risk populations

Disasters occur when natural hazards, like floods, interact with exposure, vulnerability and capacity conditions. A natural hazard will only become a disaster if it impacts the workings of a society or community. Societies make economic, planning and socio-economic decisions that shape their vulnerability to the hazard. Often, it is populations who have been pushed to the margins of society and face structural inequalities that are most at-risk to disaster impacts.

In this disaster, low-income older adults needed relief support, particularly those who have been pushed into housing that is located on floodplains and in the wildland-urban interface. Some older adults may have unique recovery needs or may be more at-risk compared to other populations, and their specific needs cannot be ignored

On the other hand, older adults often provide essential volunteer services, a financial safety net for younger, less-established family members and emotional support to others affected. It is important to include older adults in disaster recovery and consider the contributions they can make in their communities.

There are more than 170,000 homeless people living in California and these individuals face significant challenges in the aftermath of the disaster. The Governor’s Office of Emergency Services has met with representatives of community agencies and nonprofits across California to connect homeless people and other vulnerable groups with resources and shelters. Recovery support for safe shelter and mental health will be needed.

CDP has heard from philanthropic groups in California that tribal nations and mixed immigration status families needed support. Indigenous peoples and tribal nations will require resources and partnership to meet immediate needs and longer-term recovery priorities. It is important that tribal nations’ sovereignty is acknowledged and respected and that engagement is based on relationship and trust. Mixed immigration status families were frightened and may not be eligible for or feel comfortable accessing certain services being offered, especially those coming from government agencies.

Farmworkers generally experience a high level of poverty and few have employment benefits or access to unemployment benefits. In California, farmworkers were concerned about the state’s drought and its impact on their livelihoods. During the storms, they lost out on work and wages and may face health risks in returning to work.

Cash assistance

A critical ongoing need will be unrestricted cash transfers to support affected families. Direct cash assistance allows families to secure emergency housing, purchase items and contract services locally that address their multiple needs. It gives each family flexibility and choice, ensuring that support is relevant, cost-effective and timely. Cash assistance can also help move families faster toward rebuilding their lives.

In terms of donations to groups working to meet immediate needs and support long-term recovery, cash is king in disaster situations. Cash is cheaper than in-kind donations of goods and products, can be used flexibly as the situation changes and supports the local economy. Click To Tweet

In California, farmworkers are regularly being displaced and harmed during disasters, including following the storms in early 2023. In addition to damages to property or other assets, laborers, such as farmworkers, often lose wages because they cannot work after a disaster. An initiative in Sonoma County offered low-income residents disaster relief funds for lost wages and property damage due to the storm. Philanthropy can support similar initiatives to help the people most affected and marginalized recover.

House rebuilding

Thousands of homes across the state were damaged or destroyed, displacing families and disrupting their lives.

Long-term recovery will need to include support for rebuilding damaged homes and finding safe, affordable housing for people whose homes were destroyed.

Investments in preventing future disasters

While support for immediate needs and lifesaving assistance is critical following a disaster, investments in and planning for disaster recovery, preparedness and mitigation are needed. Look at the root causes of vulnerability in the community and consider how to address them, provide unrestricted dollars to strengthen nonprofit partners before the next disaster, support better planning and preparedness and build disaster resilience.

Mental health support

There will be a need for long-term mental health support, given the extent of the disaster. People may be reluctant to seek support, which means it needs to be based locally within traditional support services, such as faith communities or trusted local partners.

Our Disaster Recovery Fund provides support for flood-affected communities. Grants will be focused on supporting marginalized communities in the recovery phase.

Contact CDP

Philanthropic contributions

If you have questions or need help with making a donation to the CDP Disaster Recovery Fund, please contact development.

(Photo: Major storm damage on a state highway in California, Jan. 15. 2023. Source: Caltrans District 7)

Recovery updates

If you are a responding NGO or a donor, please send updates on how you are working on recovery from this disaster to Tanya Gulliver-Garcia.

We welcome the republication of our content. Please credit the Center for Disaster Philanthropy.

Donor recommendations

If you are a donor looking for recommendations on how to help with disaster recovery, please email Regine A. Webster.

Note: If you are an individual who was affected by the disaster, we encourage you to contact your local 211 to see what resources are available in your community.

Philanthropic and government support

In partnership with Google, CDP awarded the following grants.

  • $30,000 to Scopa Has a Dream (dba Corazon Healdsburg) in 2023 to provide direct financial assistance to cover expenses such as food, rent, utilities and other urgent unmet needs for farmworkers and low-income residents affected by the flooding in Northern Sonoma County. This funding will ensure that vulnerable farmworkers’ immediate needs are met, and they can remain housed and continue to work and support themselves and their families.
  • $50,000 to United Way of Santa Cruz County in 2023 to provide immediate, short-term support and build resiliency in communities displaced by the winter storms. During the relief phase, the project will provide emergency financial assistance with temporary lodging and food replacement for uninsured households. United Way’s efforts will build from the Santa Cruz County Long-Term Recovery Group that was established with support from CDP.

Philanthropy California hosted a disaster briefing on Jan. 18 from 1-2 p.m. PST to discuss how philanthropy and the state can best collaborate to build community resilience. The briefing was co-hosted by Philanthropy California, the League of California Community Foundations and the California Office of Emergency Services. CDP was a sponsor of the event. The event recording can be found here.

The Council on Foundations summarized resources available for philanthropy following the California storms, including resources from CDP.

The Philanthropy California team has vetted a list of funds from across the state to help donors understand the opportunities available to support place-based relief and recovery efforts from various disasters, including the January 2023 storms.

On Jan. 9, President Joe Biden approved an emergency declaration for California. Then, on Jan. 14, President Biden approved California’s major disaster declaration. As of April 18, the declaration (DR-4683) was closed to applications for disaster assistance. The declaration provided Public Assistance for several categories to eligible counties and Individual Assistance was available in Alameda, Amador, Calaveras, Contra Costa, Mendocino, Merced, Monterrey, Sacramento, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Cruz and Ventura counties. A total of 7,921 Individual Assistance applications had been approved for more than $45.18 million as of May 15.

A major disaster declaration provides a wide range of federal assistance programs for individuals and public infrastructure, including funds for both emergency and permanent work.

On March 1, California Governor Gavin Newsom issued a state of emergency in 13 counties, including hard-hit San Bernardino County. Then, on March 10, President Joe Biden approved California’s request for an emergency declaration freeing up additional resources for 34 affected counties.

On April 3, President Biden approved California’s request for a major disaster declaration to support recovery efforts from the storms beginning Feb. 21. As of April 18, the declaration (DR-4699) provided Public Assistance for several categories to eligible counties. Individual Assistance is available for individuals and households in Kern, Mariposa, Monterey, San Benito, San Bernardino, Santa Cruz, Tulare and Tuolumne counties. As of May 15, 2,142 Individual Assistance applications had been approved for more than $10.09 million.


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Disaster Phases

Disaster Phases

Disasters affect millions of people and cause billions of dollars in damage globally each year. To help understand and manage disasters, practitioners, academics and government agencies frame disasters in phases.



Flooding is our nation’s most common natural disaster. Regardless of whether a lake, river or ocean is actually in view, everyone is at some risk of flooding. Flash floods, tropical storms, increased urbanization and the failing of infrastructure such as dams and levees all play a part — and cause millions (sometimes billions) of dollars in damage across the U.S. each year.



Drought is often defined as an unusual period of drier than normal weather that leads to a water shortage. Drought causes more deaths and displaces more people than any other disaster.