California’s ski season started early this year, which is very promising. According to experts however, the El Niño event this winter won’t be able to end California’s four-year drought. There are several factors that play a role and determine the extent of California’s drought. A helicopter view of these factors has been outlined below:
Snowpack
For its water supply, California largely depends on gradual snowmelt from the Sierra Nevada. An average or above-average snowpack of about 39 inches of snow water content on April 1 is required.
Temperatures
Storms must be cold enough to support the snow pack in the Sierra Nevada. The average winter minimum temperature in the Sierra would need to drop by 6 degrees from last year’s average – from 32.1 to 26⁰F.
Rainfall
Precipitation needs to be about 120 percent of average, which is 60 inches in key Northern California watersheds.
Reservoirs
The state’s key reservoirs are at one-third of their capacity or less. Above normal rain levels are needed for storage levels to recover this winter.
Groundwater
Groundwater levels are down by as much as 100 feet in some areas. According to experts, recovery will be a multi-year process that depends on how basins are recharged and how much water continues to be pumped.
Water allocation
In 2015, farmers received 8.7 million acre-feet less surface water. Urban areas also have seen reduced deliveries and are subject to mandatory conservation. Restored water deliveries for farmers and lifting of emerging conservation measures will be a sign of drought recovery.