Bill Lynch: What’s normal about our rainfall?
By the end of January this year, the rainfall totals for Sonoma Valley was a little over 6 inches. In mid-month, on Martin Luther King’s birthday it gave many of us the creeps when a Santa Ana-like wind blew hard, hot and dry out of the northeast, eerily similar to recent Septembers and Octobers. In mid-January many local people were out in shorts and short-sleeve shirts. That apparel should have all been packed away in the closet until this spring.
Since then we’ve had a few systems bring in a little rain, but we’re less than half the normal average by this date.
The term “normal average,” however, is somewhat misleading. It suggests that our annual rainfall in our beautiful Valley of the Moon is fairly consistent. Based on a lifetime of living here and from reading old files of the Sonoma Index-Tribune, the only consistent thing about our rainfall is inconsistency.
The way things are going so far in 2021 it looks like it is going to be one of the far less than normal dry years.
Of course, it could change. At the end of January 2014 we were sitting at a seasonal total of only 6 inches of rain. Then we got two big storms in February totaling more than 12 inches. It didn’t bring us completely out of the drought but went a long way in filling our reservoirs.
Over my lifetime in Sonoma Valley there have been many drought years. In scanning old issues of the Index-Tribune, there’s plenty of evidence that droughts are a regular part of life here in our lovely vale.
During the late 19th and early 20th centuries, when the valley was primarily engaged in agriculture, the question most often asked seemed to be if there was going to be enough rain for crops.
Michael Anderson, a state climatologist with the California Department of Water Resources, says that our state has the largest wet-to-dry variability year to year than any in the union. For example: February 2019, one of our wettest on record, was followed by February 2020, one of the driest.
The driest year in my memory was 1977, when, at the end of January, we only had 6 inches of rain. That month the city declared a water emergency. Both the City of Sonoma and the Valley of the Moon Water District drafted ordinances outlining procedures for water rationing.
Local residents submitted ideas for conserving water included this list, which was published in the Index-Tribune:
— Round up the neighborhood children and have them share a bath with your kids.
— Couples should start sharing showers if they’re not already.
— Even then, you should get wet, turn off the water, lather up with soap, and then turn it back on again, just long enough to rinse the soap off.
— Turn off the tap while you’re brushing your teeth.
— Cut the number of times you flush your toilet. One family cut their flushes from 20 a day to five – a savings of about 60 gallons of water a day.
By the end of our normal rainy season in 1977 we’d had only 11 inches of rain, about one-third of normal. But at least some of us had a good time showering together.
Since then, we’ve had many more droughts, some lasting six or seven years. Low-flow toilets have replaced the low-tech solution of putting a brick into the tank. Many of us have taken out our lawns and planted gardens requiring less water. Since the late 20th Century, the city has added water storage. But the planet is getting warmer, and the frequency of drought years seems to be growing.
The closer we get to spring, the less chance we have to reach our normal average for the year. That doesn’t mean that the La Niña storm track pattern that has pushed the rain north could not shift to the south and bring in a few of those “atmospheric rivers.” If we got some of those in late February and March, we might at least get our reservoirs filled.
It may not yet be time for water rationing, but it’s probably OK to shower together anyway.