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.
[Lingering La Niñas may help forecasters spot costly weather patterns two years away]
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.
