Last week’s system did very little to alleviate record-dryness across the state. There is currently no precipitation in sight for the next 1-2 weeks. The results of the most recent snow survey released this week show the Sierra snowpack has the least water content since 1988…with parts of the Northern Sierras at less than 30% of normal. Even though parts of SoCal have seen less than 20% of normal rainfall for this 06-07 water year, this low number is even more troubling in these more northerly regions where a defecit of 60-70% translates to, in some cases, 40-50 inches liquid equivalent. The hills are already browning up here (late March!), so I think the natural growing season is going to come to a very early end in NorCal (and in parts of SoCal, it has already ended). We are very lucky that last year produced well-above normal precip in NorCal…our reserviors (and, as a result, the CA aqueduct for those down south) will remain sufficiently full for the next 6 months, at least. With the developing La Nina in the equatorial Pac, however, the 6-18 month period could become very precarious in CA. Weak to moderate La Nina events have a high correlation to below normal rainfall in the southern 2/3 of the state, and a moderately strong correlation in the northern 1/3. Two consecutive years of below normal rainfall, even if it’s not as bad as this year, could cause very serious water shortages. Locally supplied towns and cities in NorCal could actually begin to see shortages as early as this summer…Santa Cruz may implement volunatary water restrictions in May. Side note: latest CPC drought monitor moved the D0 contour up to include the Bay Area, so now 80% of the state is covered with some shade of orange or red.
