Los Altos Weather – No Rain in May

California’s drought continued in May. In our home town in Silicon Valley, it didn’t rain in May. Here’s our monthly rainfall starting in January 2013. The red bars show the rainfall we received; the blue bars show our normal rainfall based on historical averages. For most months we’ve had much less rain than normal. For three months this year, we had significant rain, but still below normal.

Los Altos Rainfall, May 2014
Los Altos Rainfall, May 2014

In every month except last September, when we received a half inch of rain, it has rained less than normal. The continued below-normal rainfall is reflected in the cumulative rainfall chart below, where blue is normal and red is actual rainfall. And we’ll receive scant rainfall for the next four months. From my post, the summer of our Mediterranean climate is much drier than Tuscany’s, for example.

Cumulative Los Altos Rainfall, May 2014
Cumulative Los Altos Rainfall, May 2014

Our drought deepens, and California’s snowpack is 18% of normal. California’s governor and local water agencies have called for water reductions, and local agencies announced new incentives to reduce water consumption by replacing appliances and lawns.

In our area, water conservation is voluntary, and there are no restrictions to conserve water, such as not watering in the heat of the day to reduce evaporation.

We don’t have the right incentives to conserve water. The local water company hasn’t raised rates for households using more water, and everyone got charged more because we reduced our water consumption. When we collectively reduced our water usage, that reduced the water company’s revenue. They needed more revenue to pay for their fixed costs, and the public utility commission approved a charge to everyone’s water bill. The process is reasonable, but we got charged extra because we reduced our usage, and rates for heavy users weren’t increased.

Agriculture remains California’s largest water user. Per this article most water districts aren’t following laws to charge farmers based on the amount of water they use. Most farmers are charged per acre irrigated, rather than based on how much water they use. Per the 2007 law, California water districts are required to charge customers based on their usage and report compliance to the state. Seven years later, eighty per cent of the water districts haven’t filed the required report on how well they’re complying with the law. Some water districts weren’t aware of the law. We want farmers to use less water, but we’re not tracking usage and charging based on water usage.

Groundwater is a major source of water, and pumping underground water is not regulated in California. California landowners have the right to pump as much groundwater as they want. As water deliveries drop, more groundwater is being pumped. But our aquifers are limited, and when more groundwater is pumped than is replenished, the ground subsides, resulting in permanent loss of capacity to store groundwater.

Groundwater overdrafts and subsidence happened in our valley. In this photo I’m standing on top of a levee separating the town of Alviso from the San Francisco Bay. The San Francisco Bay is on the left of the levee, and the trucks on the right are on a road in town.

Alviso levee
Alviso levee

In the next picture, you can see that the walkway leading out to a pier, and the walkway is just above sea level. The trucks are many feet below sea level. Alviso used to be above sea level. After electric pumps were used to pump too much groundwater from the aquifer, Alviso has sunk below sea level.

bay from Alviso levee
bay from Alviso levee

In May the overnight low temperatures were higher than normal, continuing this year’s trend.

Los Altos Temperatures, May 2014
Los Altos Temperatures, May 2014

Noting this year’s trend of warmer-than-normal weather, we gambled and transplanted tomato seedlings a month early, before our April safari. Our April temperature was warmer than normal, and we were rewarded with set fruit on our return.

Beyond the San Francisco Bay Area, California’s central valley has also been warmer than normal, affecting crops. California’s cherry crop is smaller than normal because the cherry trees didn’t get enough winter chilling.

In May we received no rain. We’ll receive little rain through September, so we’ll have to make do with the existing water supplies.  Water conservation seems to be the only tool we have to make it through the summer and save water for next year, but we have the wrong incentives to promote water conservation across rural and suburban consumers of water. This year’s trend of warmer-than-normal temperatures continues, and it is affecting our crops.


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I enjoy travel, art, food, photography, nature, California native plants, history, and yoga. I am a retired software engineer. The gravatar is a Nuttall's woodpecker that visited our backyard.

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