ARE WE SEEING A NEW DROUGHT PATTERN IN THE U.S.?
By Meteorologist Randy Mann
Article published on April 6, 2021
The Water Year across much of the West including California, Nevada and Colorado begins on October 1 as the summer seasons often have very little rain. According to the U.S. Department of Agriculture, the statewide snow water content for California ranges from 58 percent of normal in the northern portion of the state to just 35 percent in the southern regions.
In California’s Central Valley, recent rains did help a bit, but most areas are less than 60 percent of normal. At Sacramento’s Executive Airport, only 6.54 inches of rain has fallen since October 1, 2020. This is about 40 percent of average and I don’t see any major storms hitting the Golden State for at least the next several weeks.
Conditions are even drier in Southern California. Most stations have barely reported over 5 inches of rain since last October. Stations near Los Angeles have currently seen about 35 to 40 percent of normal moisture.
Water shortages are becoming a major concern in California. Water levels at the large reservoirs are approximately 55 to 65 percent of average for this time of year. According to the Sacramento Bee, the current water supply has not reached the levels seen in 2014 and 2015 when the state was very dry. During that time, drought emergencies were declared and residents were not allowed to water their lawns.
Around the rest of the country, extreme drought conditions have migrated into Texas, especially the western portions. The northern Great Plains are now seeing extreme drought conditions. Parts of Arizona, Nevada, New Mexico, Utah and Colorado are reporting “exceptional drought” conditions. Drier than normal conditions are now expanding into the Upper Midwest and the Northeast as we see this big drought pattern moving into the Corn Belt by this summer.
According to the National Weather Service, thanks to the lack of a monsoon season, Las Vegas went a record 240 days from April to December of 2020 without any measurable rainfall. Yuma, Arizona went 242 days without any rain last year. Phoenix, Arizona had 110 consecutive days without rain and the desert areas in California had over 200 days without moisture. Many stations in the Desert Southwest also reported one the driest Februarys in history.
In September of 2020, I reported on a recent study from Columbia University that was published in Science Advances, that the western U.S. has experienced one of its driest 20-year periods in approximately 1,000 years. Despite a few wet years, the southwestern regions may be in the midst of another “megadrought,” which, according to tree ring data, can last for decades. Since 800 A.D., evidence shows that there have been four previous megadroughts. They occurred in the late 800s, the mid-1100s, the 1200s and the late 1500s.
Researchers compared soil moisture records calculated since 2000 and concluded that the current drought is “already outdoing the three earliest ones.” The worst megadrought in the West likely occurred from 1575 to 1603. The article also states that the ancient droughts went on at least for several decades, but the one in the 1200s lasted for nearly a century.
In other parts of the U.S., most of the Great Plains are experiencing severe to extreme drought. The dryness has recently expanded eastward into Iowa, Illinois and Indiana. Parts of the northeastern U.S. are reporting dry to moderate drought levels. With the exception of pockets of abnormally dry areas, moisture totals in the Southeast to the Mid-Atlantic states are still at good levels.
