Last week’s rainfall across CA made some beneficial contributions to the Sierra snowpack and helped to extend the natural growing season in lower elevations. The first system was more impressive in SoCal; the second brought more rain to NorCal. Despite widespread late-season totals of 0.5-1.5 inches statewide, however, precip defecits are still at record levels in some places. Even after last week’s heavy downpours, 2006/2007 is still the driest season on record in Los Angeles proper and this is unlikely to change before the end of the “rainy” season. Up to 12 inches of new snow fell in the Sierras from this past storm, but most locations received less than 6 inches and nearly all of that snow will have melted by this afternoon. Statewide, the snowpack remains at about 40% of average for the date, which is an alarmingly low number. Reservoir levels are still near to slightly above average, a legacy of the last wet season’s record snowfall. Major river runoff estimates for the rest of spring and early summer range from moderately dry on northern rivers to critically dry in more southern drainage basins. As mentioned before, next year’s early-season precipitation will determine whether we have a serious water crisis in the coming year or not. La Nina…which was looking pretty impressive a few weeks ago…is currently rather anemic…though SST anomalies may increase over the next few months. In the short term, there is no significant weather to speak of…only increasingly warm and dry conditions…which will serve to dry out coastal fuels and melt what meager snowpack exists in the mountains. Although some precipitation is always possible in May, wetting rains become increasingly hard to come by this late in the season, and it’s possible that southern areas won’t see any more rain this season.
