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LinkedInJanuary was dry. So where does that leave us?
It seems clear from the last blog post that the optimism inspired by late December rains has now been overshadowed by one of the warmest and driest Januaries on record. This left me wondering what this means for California's ongoing multi year drought? We usually talk about drought in the summer, so how important is January precipitation?
Short answer: really important.
This time of year, water managers are usually paying close attention to the snowpack. Although water demand peaks in the summer months, a significant portion of the water supply actually falls as snow during the winter where it is stored in the snowpack until it melts and runs off into reservoirs in the spring. Snow accumulated in the winter (generally from October to March) provides roughly 1/3 of the total water supply for California. On average, this equates to more than 15 million acre feet of water, which is more than all of the water used by CA cities in 2010.
January is typically the wettest month and is an important contributor to the total snowpack. Unfortunately, this year two factors are resulting in below average numbers. First, it's not snowing; this January was the driest on record in many locations. Second, above average temperatures actually melted some of the snow that was accumulated in December. The resulting snowpack totals for January are not encouraging. As of February 2nd, the overall water storage in the snowpack is 22% of normal for this time of year, and only 14% of the average April 1st total (the standard date used for peak snowpack measurements). The picture is even bleaker considering that, given the three consecutive years of drought preceding this one, what we really should be shooting for is wet, not average.
Based on the current snowpack, the probability of ending the drought this water year seems low. To make up for the current drought deficit, it's estimated that California will need precipitation totals that are 150% of normal by September 30th. To achieve this, the snowfall in February and March will need to be well above average, and current forecasts are not predicting this. The most recent seasonal drought outlook issued by the National Oceanic and Atmospheric Administration (NOAA), shown here, actually predicts that drought will persist or intensify in Northern California.
Given this trajectory, it is likely that another year of drought is probable, if not certain. However, this is not to say that this year can't be better than last. I would like to close with two positive observations. First, the reservoir levels this month are actually slightly better than this time last year. Also, its only the beginning of February, which means that there are still two months left in the snow season for these numbers to improve.
