Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.
By: Christopher C. Burt , 7:39 PM GMT on April 03, 2014
California Drought Update
March precipitation was near normal for most of central and northern California following a couple of big rain/snow events between March 29-April 1 that helped boost the ground moisture and Sierra snowpack (at least in the northern two thirds of the state). Unfortunately, it was too little too late as the most recent, and last, important snow survey for the season conducted on April 1st has shown. Here are the details.
The lack of progress against the drought, in spite of the recent rains, can be seen in the latest California Drought Monitor report issued today (April 3rd). The areal coverage of D4 (Exceptional drought) has increased slightly from last week’s report although some improvement in the DF3-4 (Extreme drought) has been seen, this improvement taking place in the northern Sierra region. Drought Monitor maps created by NOAA et al.
The latest Sierra snow pack water content report (issued on April 1st) shows that statewide the snowpack is at 33% of normal. Although this is a slight improvement to the 29% of normal on March 1st, it is a dire situation, since normally the snow pack will be melting down from now on to the end of the water season on June 30th. The April 1st survey is considered the most significant of all the monthly snow surveys since statewide agricultural water allocations are be based upon the April 1st surveys. This is the 3rd consecutive year with the April 1 snowpack well below normal. On April 1, 2013 it was 46% of normal, and on April 1, 2012 54% of normal. Below are the maps and data for ALL three of the April 1 surveys 2012-2014:
Snow pack surveys for April 1, 2014 (top), April 1, 2013 (middle) and April 1, 2012 (bottom). Of course, this is why the drought has reached such a critical phase this year even though the water year has not been close to record territory. California Department of Water Resources.
As one can see from the above maps, the reason the drought has become so critical is that this is the third consecutive season with much below normal precipitation and snowfall. This season has been the driest of all three but will not go down in the record books as one of the driest single seasons on record, thanks to the normal precipitation of February and March. In fact, San Francisco’s current 11.92” seasonal total no longer ranks even in the top dozen of such (since 1849-1850). If not a drop of rain falls for the rest of the water season (until June 30th) only Bakersfield and Fresno would have a chance of establishing their all-time driest water year on record (Bakersfield’s driest such was 2.26” in 1933-1934 and Fresno’s 4.43” also in 1933-1934).
Below is a chart of how the precipitation totals stand now compared to one month ago. As one can see, slight improvements have occurred at all sites except in the far south where Los Angeles and San Diego did not receive any significant rainfall during March.
Seasonal (July 1-to date) precipitation totals for select California cities and the % of normal for such as of March 2nd (top table) and April 2nd (bottom table).
At this point in the season about 85%-90% of the total normal seasonal precipitation would normally have already fallen. No significant storms are forecast until at least April 10th and so, barring a miracle, the state must now resign itself to an extreme drought situation through at least next November.
Christopher C. Burt
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