Starting on Friday, we began to get some significant amounts of rain in this area — this after the occasional brief (at most a few hours) and tiny (on the order of .02 inches) bits of rainfall during the past month. People complained about our being in a drought, and indeed we are, but it’s last year’s drought; what we were in until recently was just California’s “dry season”, the roughly seven months of the year when it virtually never rains.
We have two kinds of seasons out here: the more-or-less standard set of four seasons in the mid-latitude northern hemisphere, with a cyclic pattern of changes in day length and temperatures, and the accompanying changes in plant life (in particular, deciduous trees have their leaves change color and drop in fall, and leaf out in spring); and two rainfall seasons, related to the day-length seasons but distinct from them (the dry season, with its midpoint in summer, and the rainy season, with its midpoint in winter). With the onset of the rainy season, grasses and similar plants turn from brown to green: the hills turn green for Christmas! Meanwhile, there are plants that come into bloom in all four of the day-length seasons, including winter; we have quite a few winter-blooming plants, many of which I’ve posted about on this blog.
There’s considerable variation in all of this, some of it having to do with latitude, elevation, and closeness to the ocean, some of it with more obscure causes. In a perfect rainy season, we’d have steady rainfall most of the day for most days over several months. I’ve experienced a few of those. But much can go wrong.
Last year we had a terrible drought, so that creeks, lakes, reservoirs, and rivers were not replenished by winter rains in the lower elevations, and hardly any snowpack accumulated in the Sierra Nevadas.
Some years we’ve had the opposite problem, with torrential rains producing flooding and mudflows. My first winter in California was a year of disastrous rainfall, and we’ve experienced others since then.
Now for some weather overview, as we pray for a good rainy season, starting now.
(more…)
