California Snowpack and Drought Shows Improvement Over Last Year

Tom Moore
Published: May 4,2016
A severe drought that has prevailed in California since 2011 is improving due to increased precipitation and a greater snowpack over the past few months. The presence of a strong El Niño heightened anticipation of a "banner" snowfall season across the Sierra Nevada, but the results were more checkered.
(MORE: Drought Emergency Ends in California)
The wet season is coming to a close, so let's see how California has fared as we go into the dry months ahead.

2015 to 2016 Snowpack Comparison

A hideous four-year drought prompted California Gov. Jerry Brown to impose mandatory water reductions in cities and towns and laid out steps to reduce water usage across the state by 25 percent in 2015. Snowpack in the mountains typically peaks around April 1, but on April 1, 2015, the statewide snowpack was the lowest on record (a pitiful 5 percent of average).

Snowpack comparison in the Sierra Nevada May 4, 2016 (left) to May 4, 2015 (right). As you can see, the amount of snowpack (purple shadings) in the Sierra is much greater than a year ago at this time.
(NOAA)

Because a strong El Niño developed in the Pacific, there was increasing hope for extremely high snowfall totals in the Sierra Nevada during the past winter season.
There were plenty of frayed nerves by the end of February 2016 when snowfall was significantly below average for the region. Increased March snowfall helped matters considerably, and by April 1, the statewide snowpack was much better than the previous year (87 percent of average) but slightly disappointing.
Since April 1, the snowpack has been melting fast and was only 60 percent of average by late April. That said, the snowpack across the highest peaks was in substantially better shape as compared to the previous year.

Drought and Reservoirs Improve

As of late April, much of California remained in an extreme drought, but there have been some improvements over the past several months.
As of the start of the water year (Sept. 29, 2015), a whopping 92 percent of the state was at least in a severe drought and 46 percent was in exceptional drought status, according to the U.S. Drought Monitor. As of late April 2016, 74 percent of the state was in at least a severe drought with 21 percent in an exceptional drought. These numbers are an improvement, but the state remains in a precarious situation.

California drought status as of late April 2016. Darkest red shadings correspond to the areas currently in the worst drought.

There is some better news regarding reservoir conditions.
Water levels in California's major reservoirs actually rose during the month of April from 62 percent of statewide capacity to 64 percent, according to California Data Exchange Center. In northern California, reservoirs are generally higher than historical averages as of late April. In central California, reservoirs are running a bit less than historical averages. The news is not quite as good in Southern California, where reservoirs are only about half of their historical average.

Wet Season Ending, But Some Additional Rain and Snow Ahead

California is moving quickly into a drier season.
According to the Western Region Climate Center, mountain locations in central California only receive only 2 to 3 percent of their average annual snowfall and about 5 to 10 percent of their average annual precipitation in May and June.
There is a weather system, however, that is likely to produce rain and snow for the northern and central Sierra Nevada from late this week through the upcoming weekend.
Over an inch of rain is expected in higher elevations of the northern and central Sierras and a foot or more of snow could fall at elevations above 9,000 feet. That would be equal to average precipitation for the whole month of May.

Rain and Snow Forecast Through Saturday

Could La Niña Worsen Drought Again?

Although the overall drought situation has improved over the past several months, with increased snowpack and better reservoir conditions, the situation remains tenuous.
The National Weather Service's Climate Prediction Center predicts that the fading El Niño will transition to more neutral conditions by summer, and there is a possibility that a La Niña could develop late in the year. Historically, La Niña winters tend to produce below-average precipitation in California.
Taking this information into account, some critical decisions will have to be made regarding water conservation and allocation in the state.
The California State Water Board recently held an informational workshop to solicit input on potential adjustments to the drought emergency regulation. Action to current conservation requirements could be taken this month.
MORE: Folsom Lake Hits Record Lows During the Drought