The first significant rains of the year are helping maintain water levels in Marin’s reservoirs, while easing concerns of a drier-than-normal La Niña season after drought has gripped much of the state in the last two years.
As a result of the first storm in mid-October, 2.67 inches of rain fell at Lake Lagunitas, where the Marin Municipal Water District takes measurements. The rain total since July 1 is now 2.72 inches, ahead of the 2.05 inches on average seen at this time of year historically. Marin averages about 53 inches of rain a year.
The rains have helped drop water into Marin Municipal’s seven reservoirs, which are at about 77 percent of capacity. Reservoirs for this time of year are typically 67 percent full. The district provides water to customers from Sausalito to San Rafael.
Despite the good start to the season, water district officials say conservation still should be top of mind.
“Whether it’s raining or a drought, the new normal is conservation,” said Lon Peterson, water district spokesman. “We still want to be cautious.”
The North Marin Water District in Novato has tallied .91 of an inch since July 1, compared to .09 of an inch at this time last year. The Sonoma County Water Agency reports average rainfall so far. Marin Municipal gets about 25 percent of its water from Sonoma, while North Marin gets 80 percent, with its balance coming from Stafford Lake, which is 42 percent of capacity.
Rain totals from the first storm included 3.61 inches on Mount Tamalpais, 2.52 inches in Kentfield, 2.17 inches in Olema, 1.85 inches in the Marin Headlands and 1.78 inches at Point Reyes Station, according to the National Weather Service. The northern pocket between Petaluma saw less rainfall with only 0.87 inches in Novato.
In the spring, the National Oceanic and Atmospheric Administration issued a La Niña watch for the first time since May 2012. The opposite of El Niño, a La Niña shift in Pacific Ocean temperatures often means a drier-than-normal winter. In April, scientists at NOAA said there was a 71 percent chance of La Niña conditions being present in the Pacific Ocean by November, up from 57 percent the month prior. The chances of La Niña then jumped to 75 percent in June.
But in July, the chance of a La Niña dropped to around 55 to 60 percent, and then to 40 percent in August and forecasters dropped the La Niña watch. But last weak forecasters switched gears, saying there is now a 70 percent chance that La Niña conditions will develop this fall.
“However, any La Niña that develops is likely to be weak, and forecasters aren’t quite as confident that La Niña conditions will persist long enough to be considered a full-blown episode, giving it a 55 percent chance through the winter,” NOAA research scientist Emily Becker wrote in a blog.
Article from marinij.com, co-authored by Adrian Rodriguez & Mark Prado.