Climate Matters•December 7, 2022
Drought and Deluge in 2022
KEY CONCEPTS
In 2022, some parts of the U.S. received far more precipitation than normal, while other parts received far less than normal, contributing to widespread drought.
Much of the West, Southwest, Northwest, and central and southern Plains—comprising 42.5% of the contiguous U.S.—have experienced 40 or more consecutive weeks of drought in 2022.
Meanwhile, other parts of the country have been far wetter than normal during 2022—including the Northern Rockies and Plains, the Ohio Valley region, and much of the Southeast.
Year to date precipitation accumulation charts compare 2022 precipitation to the record wettest and driest years in 240 U.S. locations
2022 has been a year of precipitation extremes. While some parts of the country have received far more precipitation than normal, other parts have received far less than normal, contributing to widespread drought.
Either extreme—from prolonged drought to flash flooding—can have a range of devastating impacts on people, ecosystems, water resources, and major sectors such as agriculture. Here, we explore the drought and precipitation data that divided the U.S. between parched and drenched in 2022.
The dry side of 2022
As of Nov 1, 85.3% of the contiguous U.S. (nearly 75% of the population) was abnormally dry or in drought, according to the U.S. Drought Monitor. That’s the largest area to be affected since the Drought Monitor was launched in 2000. Conditions have improved slightly in the weeks since, but the total abnormally dry and drought-affected area remains above 80% of the contiguous U.S.
All of California, Nevada, Utah, and New Mexico, as well as most of the rest of the Southwest, the Northwest, and large areas of the South and Plains have experienced 40 or more consecutive weeks in drought classified as moderate or higher in 2022.
In contrast, most of the eastern half of the U.S. experienced far shorter periods of drought. The Upper Midwest and parts of Arkansas, Louisiana, and Mississippi experienced 10-20 consecutive weeks of drought. Much of the rest of the eastern U.S. experienced 10 or fewer consecutive weeks of drought, with a few exceptions localized along the coastal Carolinas and parts of New England.
Drought and climate change
Rising temperatures are worsening the risk of drought in parts of the U.S. (see Climate Central’s Drought Toolkit). Warming air increases the potential evaporation from land and transpiration from plants. This process increases the water available for precipitation in some areas but contributes to drying in other areas—such as the southwestern U.S., which is experiencing the most severe megadrought of the past 1,200 years. Over 40% of the southwestern megadrought (2000-2021) severity is attributed to human-caused climate change. Risks of severe and prolonged megadroughts in the Southwest are projected to intensify over this century with continued warming.
Drought impacts
Drought is measured using several indicators that reflect the status of a region’s water cycle. These indicators can include precipitation, streamflow, groundwater and reservoir levels, soil moisture, and snowpack.
The 2022 year to date (through November 30) precipitation has been far lower than normal across parts of the West and Great Plains that have experienced unrelenting multi-year drought—particularly in large swaths of central and northern California, southern Oregon, central Idaho, and south-central Texas that have received up to 20 inches less precipitation than normal.
At over $10 billion per event, drought has the second-highest price tag of all types of billion-dollar weather and climate disaster events in the U.S. Droughts can:
lead to crop failure or pasture losses
cause short- and long-term public health impacts
reduce the efficiency of thermoelectric power generation
threaten outdoor recreation and tourism industries
and degrade ecosystems.
Parched rangelands and forests also increase the fuel for wildfires.
Drought to continue and expand
According to NOAA’s Winter 2022 U.S. Drought Outlook, widespread drought conditions are likely to continue across much of the West, the Great Basin, and the central-to-southern Great Plains. Drought is also expected to expand across the South-central region and into the Southeast. On the other hand, drought is expected to improve or end across much of the Northwest.
This drought outlook is broadly consistent with precipitation patterns during the previous two La Niña winters, which were marked by lower than normal precipitation across the western U.S., Plains, and South—and wetter than normal conditions in the Ohio Valley and the Northwest. There is a 76% chance of La Niña during December-February of 2022-23, making this the third time since 1950 that the U.S. has experienced three consecutive La Niña winters.
A dry winter in the already drought-stricken West raises concerns about water availability during 2023. Winter precipitation that accumulates as mountain snowpack across the West acts as a critical source of warm season water supplies—recharging groundwater and reservoirs that support public water supplies and irrigation for agriculture in the region.
In many western locations across California, Oregon, and Washington, winter precipitation accounts for 40-50% or more of average annual precipitation—compared to 10-30% for most of the rest of the contiguous U.S.
The wet side of 2022
While much of the West and Plains are dealing with drought, other parts of the country have been far wetter than normal—including the Ohio Valley region (reflecting the historic heavy rainfall and flash flooding that devastated eastern Kentucky in July 2022) and much of the Southeast (reflecting the heavy rainfall and damaging floods associated with Hurricane Ian in September 2022).
Of the 240 U.S. locations analyzed:
147 locations had at least one 24-hour rainfall totaling 2 inches or more. Locations with multiple 2-inch rainfall events were concentrated in the Southeast, South-central, and Ohio Valley regions.
34 locations had at least one 24-hour rainfall totaling 4 inches or more. Locations in Florida, Mississippi, and Missouri experienced multiple 4-inch rainfall events.
Six locations had 24-hour rainfall totals exceeding 6 inches:
St. Louis, Mo. received 8.64 inches of rainfall on July 26, causing historic flash flooding across the metro area.
Orlando and Sarasota, Fla. received 7.72 and 6.67 inches, respectively, on September 28 during Hurricane Ian.
Birmingham, Ala. received 6.97 inches on June 8, contributing to significant flash flooding across central Alabama.
Laredo, Texas received a record-breaking 6.82 inches of rainfall on August 15.
Beaumont, Texas received 6.20 inches of rainfall on July 1.
Heavy rainfall and climate change
Because a warmer atmosphere can hold more moisture, climate change is increasing the frequency of extreme precipitation (see Climate Central’s Heavy Rain and Flooding Toolkit). A recent study found significant shifts toward higher daily precipitation intensities since the 1950s—especially in the central and eastern U.S. Heavier downpours increase the risk of hazardous flash flooding and landslides.
POTENTIAL LOCAL STORY ANGLES
How is drought affecting your local area?
The Drought Impact Reporter Dashboard, maintained by the National Drought Mitigation Center at the University of Nebraska, documents and maps county, state, and territory-level drought impacts on a range of sectors including agriculture, energy, public health, fire, and wildlife. State-level drought impacts can be filtered by a range of criteria using a U.S. Drought Monitor web tool.
How are heavy downpours affecting your local area?
Monitor current conditions using NOAA’s excessive rainfall outlook, which forecasts the probability that rainfall will exceed flash flood guidance in a given area. Refer to the excessive rainfall climatology for a summary of high flood risk areas and days since 2016, and a list of flood-associated casualties and property losses since 2010. NOAA’s Interactive Flood Information Map summarizes flood hazards in each state and provides relevant forecast and safety information.
LOCAL EXPERTS
The SciLine service, 500 Women Scientists or the press offices of local universities may be able to connect you with local scientists who have expertise on precipitation extremes and climate change. The American Association of State Climatologists is a professional scientific organization composed of all state climatologists.
NATIONAL EXPERTS
Samuel Sandoval, PhD
Professor
Cooperative Extension Specialist in Water Management
University of California, Davis
Contact: samsandoval@ucdavis.edu
*interviews available in English and Spanish
Mark Svoboda, PhD
Director and Associate Professor
National Drought Mitigation Center
University of Nebraska-Lincoln
Contact: msvoboda2@unl.edu
Related expertise: drought monitoring, early warning, and impacts; drought risk management; climatology
Kevin Reed, PhD
Associate Professor and Associate Dean for Research
School of Marine and Atmospheric Sciences, Stony Brook University
Contact: kevin.reed@stonybrook.edu
Related expertise: Tropical cyclones, extreme weather, climate change, and event attribution
METHODOLOGY
Daily precipitation data was retrieved for 240 U.S. cities using the Applied Climate Information System. 2022 precipitation data is year-to-date (through 11/30). 24-hour rainfall totals provided above are for calendar day 24-hour periods. Local accumulation graphics were not created for Albany, Ga.; Bend, Ore.; Glendive, Mont.; Greenville, Miss.; Idaho Falls, Idaho; Lafayette, Ind.; or Presque Isle, Maine due to insufficient data.
The cumulative weeks of drought map was generated using county data from the U.S. Drought Monitor. Values represent the longest cumulative weeks of drought (D1-D4, minimum of two weeks) in 2022 through 12/1/2022.