The Enterprise Bridge over California's Lake Oroville, where water levels have dropped to 40 percent of capacity. (Justin Sullivan/Getty Images)
By Diana Leonard and

California’s deepening drought has worsened into a crisis, as a second dry year in a row has diminished the state’s water supply and another difficult fire season looks inevitable. Nearly three-quarters of the state is in extreme to exceptional drought. With the wet season all but over and a hot, dry summer probably ahead, water shortages and fire danger are poised to intensify.

The past several weeks have shown dramatic change in drought status: Extreme drought has expanded through the northern Sierra’s crucial water region and in the agricultural San Joaquin Valley.

Exceptional drought, the worst category in the federal government’s U.S. Drought Monitor, has descended upon the Bay Area and the nearly snow-free southern Sierra. Moderate drought conditions or worse cover all of California.

Extreme drought conditions prevail

throughout the southwest

Exceptional

drought

Extreme

drought

Severe

drought

Moderate

drought

The governor has declared a drought emergency in

41 counties due to extreme dry conditions in most of the state.

Sacramento

San

Francisco

CALIFORNIA

Bakersfield

Los Angeles

Extreme drought conditions prevail

throughout the southwest

Exceptional

drought

Extreme

drought

Severe

drought

Moderate

drought

The governor has declared a drought emergency in

41 counties due to extreme dry conditions in most of the state.

Oroville

Reservoir

Sacramento

San Francisco

CALIFORNIA

Bakersfield

Pacific

Ocean

Los Angeles

Extreme drought conditions prevail throughout the southwest

Exceptional drought

Abnormally dry

The governor has declared a drought emergency in

41 counties due to extreme dry conditions in most of the state.

Oroville

Reservoir

Sacramento

San Francisco

CALIFORNIA

Bakersfield

Los Angeles

Extreme drought conditions prevail throughout the southwest

Exceptional drought

Abnormally dry

The governor has declared a drought emergency in

41 counties due to extreme dry conditions in most of the state.

Salt Lake City

Oroville

Reservoir

Sacramento

San Francisco

CALIFORNIA

Bakersfield

Pacific

Ocean

Los Angeles

Extreme drought conditions prevail throughout the southwest

Exceptional drought

Extreme drought

Severe drought

Moderate drought

Abnormally dry

The governor has declared a drought emergency in

41 counties due to extreme dry conditions in most of the state.

Salt Lake City

Oroville

Reservoir

Sacramento

San Francisco

CALIFORNIA

Bakersfield

Los Angeles

Pacific

Ocean

Cindy Matthews, senior hydrologist with the National Weather Service’s Sacramento office, said the recent drought progression is a result of the dry winter, which has been followed by a very warm and dry spring. Most of the state has received less than a half-inch of rain since April 1.

[Drought-plagued California and western U.S. may see another devastating fire season]

California Gov. Gavin Newsom (D) has declared a drought emergency in 41 counties, a move that will help to conserve water in reservoirs, although many sectors will vie for that limited supply downstream, including households, farmers and freshwater ecosystems.

“There is not enough water available, so reservoir operators have reduced their allocations to those who have rights to that water,” Matthews said in an interview. There are reports of farmers allowing fields to go fallow this spring because there probably will not be enough water to sustain some crops through the season. Freshwater fish species such as salmon are also threatened by low stream levels.

In just over a year, a parched and burned

landscape and lower reservoir levels

May 2020: Reservoir at 70% of capacity

Oroville

Reservoir

Enterprise

Bridge

Oroville Dam

May 2021: Reservoir at 42% of capacity

Area burned by

North Complex Fire

in August/October

of 2020

Fire perimeter

In just over a year, a parched and burned

landscape and lower reservoir levels

May 2020: Reservoir at 70% of capacity

Oroville

Reservoir

Enterprise

Bridge

Oroville Dam

May 2021: Reservoir at 42% of capacity

Area burned by

North Complex Fire

in August/October

of 2020

Fire perimeter

In just over a year, a parched and burned landscape

and lower reservoir levels

May 2020:

Reservoir at 70% of capacity

May 2021:

Reservoir at 42% of capacity

Area burned by

North Complex Fire

in August/October

of 2020

Oroville

Reservoir

Fire perimeter

Enterprise

Bridge

Oroville Dam

In just over a year, a parched and burned landscape and lower reservoir levels

May 2020:

Reservoir at 70% of capacity

May 2021:

Reservoir at 42% of capacity

Area burned by

North Complex Fire

in August/October

of 2020

Oroville

Reservoir

Enterprise

Bridge

Fire perimeter

Oroville Dam

In just over a year, a parched and burned landscape and lower reservoir levels

May 2020:

Reservoir at 70% of capacity

May 2021:

Reservoir at 42% of capacity

Area burned by

North Complex Fire

in August/October

of 2020

Oroville

Reservoir

Enterprise

Bridge

Fire perimeter

Oroville Dam

The drought is hitting especially hard in the wetter northern half of the state, where major reservoirs are fed by mountain snowmelt. The two largest of those, Lake Shasta and Lake Oroville, are at 46 percent and 40 percent, respectively, of their total capacity this week and are lower than they were at this date during the 2012-2016 drought. Because of climate change, the prolonged dry spells of the past 10 years are much warmer and therefore more severe than those that occurred decades ago.

[California’s rainy season now starts nearly a month later, increasing wildfire risks]

Disappearing snowpack

The state’s snowpack, which represents 30 percent of its water supply, stores water high in the mountains and delivers it to surrounding forests, rivers and eventually to reservoirs, in late spring and summer. Most of the streamflow in the Sierra Nevada region comes directly from snowmelt.

Sierrra Nevada snowpack

evaporates in two months

March 28: Peak snowpack,

but only 63% of normal

Pacific

Ocean

Cloud cover

NORTHERN SIERRA

SACRAMENTO

VALLEY

Sacramento

Lake Tahoe

CENTRAL SIERRA

SAN JOAQUIN

VALLEY

SOUTHERN SIERRA

Cloud

cover

Bakersfield

M O J A V E

D E S E R T

Los Angeles

May 10: Snowpack is down to 8%;

a week later it is 4%

Pacific

Ocean

NORTHERN SIERRA

SACRAMENTO

VALLEY

Sacramento

Lake Tahoe

CENTRAL SIERRA

SAN JOAQUIN

VALLEY

SOUTHERN SIERRA

Cloud

cover

Bakersfield

M O J A V E

D E S E R T

Cloud

cover

Los Angeles

Sierrra Nevada snowpack evaporates in two months

March 28: Peak snowpack, but only 63% of normal

Pacific

Ocean

Cloud cover

NORTHERN SIERRA

SACRAMENTO

VALLEY

Sacramento

Lake Tahoe

CENTRAL SIERRA

San

Francisco

SAN JOAQUIN

VALLEY

SOUTHERN SIERRA

Cloud

cover

Bakersfield

M O J A V E

D E S E R T

Los Angeles

May 10: Snowpack is down to 8%; a week later it is 4%

Pacific

Ocean

NORTHERN SIERRA

SACRAMENTO

VALLEY

Sacramento

Lake Tahoe

CENTRAL SIERRA

San

Francisco

SAN JOAQUIN

VALLEY

SOUTHERN SIERRA

Cloud

cover

Bakersfield

M O J A V E

D E S E R T

Cloud

cover

Los Angeles

The Sierrra Nevada snowpack evaporates in two months

March 28:

Peak snowpack,

but only 63% of normal

May 10:

Snowpack is down to 8%;

a week later it is 4%

Pacific

Ocean

Cloud cover

NORTHERN SIERRA

NORTHERN SIERRA

SACRAMENTO

VALLEY

SACRAMENTO

VALLEY

Sacramento

Sacramento

Lake Tahoe

Lake Tahoe

CENTRAL SIERRA

CENTRAL SIERRA

SAN JOAQUIN

VALLEY

SAN JOAQUIN

VALLEY

SOUTHERN SIERRA

SOUTHERN SIERRA

Cloud

cover

Cloud

cover

Bakersfield

Bakersfield

M O J A V E

D E S E R T

M O J A V E

D E S E R T

Los Angeles

Los Angeles

The Sierrra Nevada snowpack evaporates in two months

March 28:

Peak snowpack,

but only 63% of normal

May 10:

Snowpack is down to 8%;

a week later it is 4%

Pacific

Ocean

Cloud cover

NORTHERN SIERRA

NORTHERN SIERRA

SACRAMENTO

VALLEY

SACRAMENTO

VALLEY

Sacramento

Sacramento

Lake Tahoe

Lake Tahoe

San

Francisco

San

Francisco

CENTRAL SIERRA

CENTRAL SIERRA

SAN JOAQUIN

VALLEY

SAN JOAQUIN

VALLEY

SOUTHERN SIERRA

SOUTHERN SIERRA

Cloud

cover

Cloud

cover

Bakersfield

Bakersfield

Santa Barbara

Santa Barbara

M O J A V E

D E S E R T

M O J A V E

D E S E R T

Los Angeles

Los Angeles

The Sierrra Nevada snowpack evaporates in two months

March 28: Peak snowpack, but only 63% of normal

May 10: Snowpack is down to 8%; a week later it is 4%

Pacific

Ocean

Cloud cover

NORTHERN SIERRA

NORTHERN SIERRA

SACRAMENTO

VALLEY

SACRAMENTO

VALLEY

Sacramento

Sacramento

Lake

Tahoe

Lake

Tahoe

San

Francisco

San

Francisco

CENTRAL SIERRA

CENTRAL SIERRA

SAN JOAQUIN

VALLEY

SAN JOAQUIN

VALLEY

SOUTHERN SIERRA

SOUTHERN SIERRA

Cloud

cover

Cloud

cover

Bakersfield

Bakersfield

Santa Barbara

Santa Barbara

M O J A V E

D E S E R T

M O J A V E

D E S E R T

Note: Topography

and hydrography

were added to the

satellite imagery.

Los Angeles

Los Angeles

This year, though, an already paltry snowpack has melted off at breakneck speed. And instead of flowing into rivers, much of the meltwater has seeped into parched soil or simply evaporated.

“We saw massive, rapid melt-off of the snowpack at the lower and middle elevations,” Chris Orrock of the California Department of Water Resources said in an interview. Statewide snowpack, which peaked March 25 at 64 percent of average, is only 2 percent of average for the date.

April was exceedingly warm over the Sierra, and the loss of snow and streamflow illustrates how higher temperatures due to climate change can compound the effects of droughts.

There was also simply much less snow available this year. Both the northern and central Sierra are on track to record their third-driest year on record, while the southern Sierra probably will see its driest.


The Sierra Nevada peaks of Tahoe National Forest in Nevada County. (Elias Funez/Union/AP)

Over the past two years combined, some regions have missed an entire season’s worth of precipitation.

“We’ve lost a whole year of runoff in the water project that supplies water across California,” Orrock said, referring to the State Water Project, a storage and delivery system that serves 27 million Californians and irrigates Central Valley farmland.

Although major cities such as San Francisco have diverse water supply portfolios and can draw from numerous sources and backup supplies, smaller cities rely on their local reservoirs and therefore depend on rain that falls in their local watersheds.

Marin County, just north of San Francisco, draws its water from the Russian River watershed, which sits at the epicenter of the current drought. On Tuesday, the county’s board of supervisors declared a drought emergency and further tightened mandatory water restrictions, such as limiting outdoor sprinkler use, to preserve reservoir storage through the long dry season ahead.

Another challenging fire season underway early

An active fire season is already underway in California, as drought and warm conditions have led to summerlike flammability in May.


California Gov. Gavin Newsom holds a news conference in the parched basin of Lake Mendocino in Ukiah, Calif., on April 21. (Kent Porter/Press Democrat/AP)

At an event earlier this month to kick off the state’s Wildfire Preparedness Week, Cal Fire Director Thom Porter said, “We are seeing conditions right now, this year, that are a month or two down the road.”

The agency has increased staffing in preparation for another challenging season as both the number of fires and the number of acres burned so far this year are well above the five-year average.

In an ominous sign, some fires are growing large even in the absence of typical fire weather. On Sunday, the Palisades Fire northwest of Santa Monica spread in cool, humid breezes from the ocean — an indication of how flammable the landscape is. Lisa Phillips, a meteorologist with the National Weather Service in Oxnard, said current low moisture levels in the area’s live chaparral vegetation are not usually seen until July.

Most of Los Angeles and Ventura counties are in “extreme” drought; Los Angeles International Airport recorded only five inches of rain for the water year — less than half of normal.

Drought within a ‘megadrought’

Although California has always had highly variable year-to-year precipitation, in the past two decades, dry years have become more frequent, occurring three times more often than wet years. Scientists have found that the southwestern United States has been mired in a “megadrought,” the second-worst such era in the past 1,200 years. These long-term dry periods, which can last decades, are marked by low precipitation, as well as low soil moisture and snowpack.

A two-decade trend of more heat

and less rain for Californians

California mean temperature anomaly

Above average temperature

Below average temperature

Note: The average value for 12-month periods from

1950 to 2000 ending in September was 57.2° F.

California mean precipitation anomaly

Above average

precipitation

Below average

precipitation

Note: The average value for 12-month periods

from 1950 to 2000 ending in September

was 24.28 inches.

Source: PPIC Water Policy Center

A two-decade trend of more heat

and less rain for Californians

California mean temperature anomaly

Above average temperature

Below average temperature

Note: The average value for 12-month periods from 1950 to

2000 ending in September was 57.2° F.

California mean precipitation anomaly

Above average

precipitation

Below average

precipitation

-15

inches

Note: The average value for 12-month periods from 1950 to

2000 ending in September was 24.28 inches.

Source: PPIC Water Policy Center

A two-decade trend of more heat and less rain for Californians

California mean temperature anomaly

Above average temperature

Below average temperature

Note: The average value for 12-month periods from 1950 to 2000 ending in September was 57.2° F.

California mean precipitation anomaly

Above average precipitation

Below average precipitation

-15

inches

Note: The average value for 12-month periods from 1950 to 2000 ending in Sept. was 24.28 inches.

Source: PPIC Water Policy Center

A two-decade trend of more heat and less rain for Californians

California mean temperature anomaly

Above average temperature

Below average temperature

Note: The average value for 12-month periods from 1950 to 2000 ending in September was 57.2° F.

California mean precipitation anomaly

Above average precipitation

Below average precipitation

-15 inches

Note: The average value for 12-month periods from 1950 to 2000 ending in September was 24.28 inches.

Source: PPIC Water Policy Center

Increasing temperatures due to climate change have doubled down on the megadrought, meaning more water is being lost to the atmosphere, and more precipitation is falling as rain instead of snow. This warming has also translated into greatly increased wildfire risk.

“It’s obvious we’re seeing smaller amounts of snow, and it’s melting earlier — that’s the big change,” Jeffrey Mount, a senior fellow in water and climate change policy at the Public Policy Institute of California, said in an interview.

Mount described 2011 as an example of a “really good cold wet year” with rushing snowmelt in June. Such years are needed to replenish reservoirs and groundwater, but they’ve been few and far between since 1999.

A great snow pack year

compared to current conditions

Snow water equivalent (in inches)

May 10, 2011

May 10, 2021

Sacramento

Sacramento

A great snow pack year

compared to current conditions

Snow water equivalent (in inches)

May 10, 2011

May 10, 2021

Sacramento

Sacramento

CALIFORNIA

A great snow pack year compared to current conditions

Snow water equivalent (in inches)

May 10, 2011

May 10, 2021

Lake Tahoe

Sacramento

Sacramento

CALIFORNIA

CALIFORNIA

Pacific

Ocean

A great snow pack year compared to current conditions

Snow water equivalent (in inches)

May 10, 2011

May 10, 2021

Lake Tahoe

Sacramento

Sacramento

CALIFORNIA

CALIFORNIA

Pacific

Ocean

“We have an elaborate system to store and manage water, but it’s all based on 1950s hydrology — not modern hydrology,” he said. In other words, it was built around a past climate, when wet years were more reliable and less water was lost through evaporation.

“Maybe we’ll get lucky and next year we’ll go into a wet period like we had in the mid-90s, and everything will be great,” he said. “But that’s highly unlikely.”

About this story

U.S. Drought Monitor data was used for May 20. Satellite images of Lake Oroville via ESA Sentinel 2 satellite and fire perimeter data via CalFire. ESA Sentinel 3 imagery was used in the two-month comparison graphic, and California Department of Water Resources for the capacity data. Megadrought analysis provided by PPIC Water Policy Center. Snow water equivalent data via NOAA.