Drought is an insidious climate threat — by the time it has a hold of a region, impacts on ecosystems and water supplies can be locked in. It may not grab extreme weather headlines like the disrupted polar vortex or record hurricane season, but drought during 2020 and heading into 2021 is a looming story likely to grow in importance.

Intensity of drought

Abnormally dry

Exceptional drought

CANADA

Winnipeg

Seattle

Ottawa

Boise

Minneapolis

Toronto

Boston

Boston

Detroit

Salt Lake

City

New York

Chicago

San Francisco

Denver

Washington

D.C.

Washington

D.C.

Las Vegas

St. Louis

Santa Fe

Los Angeles

Atlanta

Albuquerque

Phoenix

Atlantic

Ocean

Dallas

Pacific

Ocean

Chihuahua

Houston

Miami

Gulf of

Mexico

Culiacancito

MEXICO

500 MILES

Mexico City

Intensity of drought

Abnormally dry

Exceptional drought

CANADA

Winnipeg

Seattle

Ottawa

Boise

Toronto

Boston

Minneapolis

Detroit

New York

Chicago

Salt Lake

City

San Francisco

Washington D.C.

Washington D.C.

St. Louis

Denver

Las Vegas

Santa Fe

Los Angeles

Atlanta

Albuquerque

Phoenix

Atlantic

Ocean

Dallas

Chihuahua

Houston

Pacific

Ocean

Miami

Gulf of

Mexico

Culiacancito

MEXICO

500 MILES

Mexico City

Intensity of drought

Abnormally dry

Exceptional drought

CANADA

Winnipeg

Seattle

Ottawa

Boise

Toronto

Boston

Boston

Minneapolis

Detroit

New York

New York

Chicago

Salt Lake

City

San Francisco

Washington D.C.

Washington D.C.

Denver

St. Louis

Las Vegas

Santa Fe

Los Angeles

Albuquerque

Atlanta

Phoenix

Dallas

Houston

Chihuahua

Miami

Culiacancito

MEXICO

500 MILES

Mexico City

Intensity of drought

Abnormally dry

Exceptional drought

CANADA

Atlantic

Ocean

Gulf of

Mexico

Pacific

Ocean

MEXICO

500 MILES

Intensity of drought

Abnormally dry

Exceptional drought

CANADA

Atlantic

Ocean

Gulf of

Mexico

MEXICO

Pacific

Ocean

500 MILES

The above map shows drought conditions across North America, including parts of Canada and Mexico, valid on Dec. 10.

Nowhere is this more true than in the Southwest, population growth and years of drought conditions are putting the region on a collision course with drastic water management decisions. On Wall Street, traders can now bet on California water futures on commodity markets, enabling them to hedge against future scarcity, much as they trade gold, oil and agricultural products.

The forecast persistence of La Niña, a periodic cooling of the waters in the eastern tropical Pacific along the equator, through the winter favors a worsening of drought conditions along the southern tier of the U.S.

Sea-surface temperature anomaly,

December 2020

Difference from 1981-2010 average

Cooler

Warmer

Atlantic

Ocean

Pacific

Ocean

Indian

Ocean

Sea-surface temperature anomaly,

December 2020

Difference from 1981-2010 average

Cooler

Warmer

Atlantic

Ocean

Pacific

Ocean

Indian

Ocean

Sea-surface temperature anomaly, December 2020

Difference from 1981-2010 average

Cooler

Warmer

Atlantic

Ocean

Pacific

Ocean

Indian

Ocean

In Southern California, the wildfire season finally came to an end in late December, but rains have been sporadic and light into the start of the new year. The state’s first snow survey of the year shows that the statewide snowpack was just 52 percent of average on Jan. 1. Storms are likely to increase that percentage during the next few weeks, but the dry fall has put the Golden State at a deficit that could be difficult to make up given the favored storm track.

Unlike El Niño years, which feature above average water temperatures in the tropical Pacific and can direct a relentless firehose of moisture at the West throughout the winter, La Niña winters tend to favor stormy conditions in the Pacific Northwest instead.

A total of 49 percent of the Lower 48 states were in moderate to exceptional drought conditions as of Dec. 29, with dry conditions extending north into Alberta.

Continental U.S. drought conditions

Abnormally dry

Moderate drought

Severe

Extreme

Exceptional

80% of total land area

60

40

20

0

2020

2000

2005

2010

2015

Continental U.S. drought conditions

Abnormally dry

Moderate drought

Severe

Extreme

Exceptional

80% of total land area

60

40

20

0

2020

2000

2005

2010

2015

Continental U.S. drought conditions

Abnormally dry

Moderate drought

Severe

Extreme

Exceptional

80% of total land area

60

40

20

0

2020

2000

2005

2010

2015

While droughts come and go, there is increasing evidence that parts of the U.S., namely the Southwest, are enduring long-term “megadrought” conditions seen in historical tree ring records. This is partly related to climate change, which worsens droughts by increasing temperatures, thereby turbocharging the loss of moisture from plants and soils. Climate change is also shifting weather patterns in ways that favor drier conditions in the Southwest U.S., pushing storm tracks northward.

The above chart shows the percent of total land area in the Lower 48 states that are in drought conditions. You’ll see the huge spike between 2010 and 2015, which coincided with a costly drought in Texas and California’s most intense and long-lasting drought more in than a millennium, and the recent climb that has not yet leveled off.

Probability of precipitation

Outlook for December 2020 - February 2021

Wetter than normal

Drier than normal

33%

40

50

70

80%

80%

70

60

50

40

33%

60

Probability of precipitation

Outlook for December 2020 - February 2021

Wetter than normal

Drier than normal

33%

40

50

70

80%

80%

70

60

50

40

33%

60

Probability of precipitation

Outlook for December 2020 - February 2021

Wetter than normal

Drier than normal

80%

70

60

50

40

33%

33%

40

50

60

70

80%

The seasonal precipitation forecast from the Climate Prediction Center at NOAA shows the likelihood of a La Niña-tinged winter weather pattern, with a drier than average southern tier. This would be especially bad news for states like California, New Mexico and Arizona, but also southern Texas and Florida, too.

About this story

North America drought data sourced from National Centers for Environmental Information’s North American Drought Monitor (released on Dec. 10). U.S. precipitation outlook data issued on Oct. 15 by NWS Climate Prediction Center. U.S. drought time series data as of Dec. 29, 2020.

Lauren Tierney contributed to this report.