Tuesday, January 24, 2012
In Search of Rain
Average annual rainfall varies for different San Francisco Bay area (and Santa Cruz county) towns, but where I live, 13 inches per rainfall year is normal. Last year, we managed 16 inches, and the garden looked great. This year, though, things are grim. With the rainfall year starting July 1st, we only had 1.5 inches of rain by January 10, the driest winter in recorded history.
I actually turned on the irrigation once a week and did some hand watering, but clearly the ferns under the redwoods did not consider my efforts adequate, and the Artemesia above looks as if it's destined for the compost pile.
Why is this happening? A big part of it is that it's a La Niña year. El Niño and La Niña are both weather patterns. During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean are lower than normal by 3–5 °C. This pattern results in more rain and snow in some areas (remember the news about the Alaska village?) and less rain in other areas.
During a La Niña year, southern California has below normal percipitation fairly reliably (see this discussion). For Central California, the situation is a little more open ended. The dividing line between the wet northern area in a La Niña year and a dry El Nino year is around San Francisco (see this discussion). So we can have dry El Niño and wet La Niña years.
This year, though, it's been very dry. My wildflower seeds did not sprout. Half of the Manzanitas do not seem to have buds. It's been a little depressing, and not as exciting to be in the garden. So I was really happy when a series of storms was forecast for last weekend, and went in search of rain at Arastradero Open Space Preserve.
I know we usually yearn for photos with blue sky and green leaves, but I was so happy to see the rainclouds behind the native oaks. In fact, it looked as if it already rained closer to the coast - would the rain make it over here?
The lichen looked just as dried out as my ferns, but as I started heading back to the car, the first rain drops started to fall. We had a good soaking rain the first night, and a slightly less impressive storm a day later. We're not at 2.7 inches for the rainfall year, still 50% of normal but it's a start. Let's keep our fingers crossed for more - the gardens, the trees, the flowers, the critters - we all need it.