WATER YEAR 2017/18 Solid Spring Helps with Disappointing Winter By Tim Linden A series of March and April storms helped California move much closer to a normal year in terms of precipitation and helped keep the dreaded “D-word” out of the conversation for at least another year. “As of today’s date (April 16), we are still well below average with regard to snow depth,” said Doug Carlson, who is an information officer with the California Department of Water Resources. “We are only a bit over 41 percent of normal.” He said a very dry February is the major culprit. Often the wettest month of the winter, this year February checked in with only about 15 percent of its normal precipitation. But Carlson said above average rain in March and April, plus a strong reservoir position going into the water year, has helped offset the Current Regi al Snowpack f om Automated Snow Sensors
NORTH Data as of April 19, 2018 Though the numbers are looking better, Carlson said many are still concerned about the overall trend. From 2012 through 2015, those four years were historically dry. Carlson said some are wondering if the 2016/17 water year was just an outlier and dryer conditions are going to prevail once again. Again, a year that approaches 85 percent of average isn’t a huge concern assuming it is followed by a year that tops average. But, if this below-average Number of Stations Reporting 30 Average snow water equivalent (Inches) 9.3 Percent of April 1 Average (%) Percent of normal for this date (%) 34 39 less than stellar winter. Though the below average snow depth means less reservoir-filling runoff this spring, Carlson said many of the state’s largest reservoir are at or above normal as the rainy season winds down. For example on the April 16 th date, the Shasta reservoir in Northern California was at 108 percent of normal while the Don Pedro Reservoir in the Central Valley was sitting at 123 percent of normal. And that same day, Northern California was being pelted with a cold storm that was sure to deliver a late blanketing of the Sierras. Checking up-to-date data, Carlson said the state was at 84 percent of its average precipitation at its Northern California weather stations, which is where the vast majority of rain falls each year. Southern California was still tracking far below normal, but Carlson said those numbers are not as accurate as the north simply because the southern half of the state is not equipped with as many weather stations because that is not where the rain and snow typically falls and accumulates.
% of April 1 Average / % of Normal for This Date Current Regional Snowpack from Automated Snow Sensors
Northern Sierra / Trinity
34% / 39%
CENTRAL Data as of April 19, 2018
Central Sierra
Number of Stations Reporting
43
48% / 52%
Average snow water equivalent (Inches) Percent of April 1 Average (%) Percent of normal for this date (%)
14.0
48 52
Southern Sierra
33% / 36%
% of April 1 Average / % of Normal for this Date
SOUTH Data as of April 19, 2018 Statewide Average: 40% / 44%
Number of Stations Reporting
28
Average snow water equivalent (Inches) Percent of April 1 Average (%) Percent of normal for this date (%) Data as of April 19, 2018
8.4
33 36
North Central South State
Number of stations reporting
30
43
28
101
Average snow water equivalent (inches)
9.3
14.0
8.4
11.1
STATE Data as of April 19, 2018
Percent of April 1 average (%)
34
48
33
40
Number of Stations Reporting
101 11.1
Average snow water equivalent (Inches) Percent of April 1 Average (%) Percent of normal for this date (%) Percent of normal for this date (%)
39
52
36
44
40 44
16 Western Grower & Shipper | www.wga.com MAY | JUNE 2018
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