After a dry spell in February, March brought rain and snow to some parts of western U.S. Although dry conditions eased in southern California, in most of the northern two-thirds of the state the conditions remain unchanged. Extreme northern California and southern Oregon did not receive heavy precipitations and drought conditions there progressed from moderate to severe drought.
Also experiencing severe drought are a portion of south-central Idaho and a large area in the Four Corners region, which is part of the Colorado River basin. In these areas both short and long term impacts are expected, according to the USDM. Short term impacts typically last less than 6 months and affect agriculture and grasslands, but long term impacts typically last more than 6 months and affect hydrology and ecology. The USDM lists the following as possible impacts of severe drought: likely crop or pasture losses, common water shortages, and imposition of water restrictions.
Water resources in the Colorado basin are used by some 40 million people, including the Los Angeles region via the Colorado River Aqueduct. Recent studies have found that water flows in the Colorado River are decreasing due to the effects of global warming, increasing the risk of water shortages.
‘There is no quick fix to a long drought’ said climatologist Bill Patzert, pointing out that with normal rainfall, Lake Mead on the Colorado takes 17 years to fill, and that groundwater aquifers take a long time to replenish. He remarked that it will take more than one wet year in the Sierra Nevada to end the drought.
On the other hand, this month’s rainfall will promote growth of vegetation such as grass and weeds, which act as flashy fuel for wildfires, warned Scott McLean of California’s Department of Forestry and Fire Protection.