Unlike other weather phenomena, drought can sneak up on us. We don't realize that we're in a drought until well after it's started. And we can't look at a radar map to know with any certainty when a drought will end. And while we've had some rainfall this autumn, we clearly remain in the midst of the most severe drought conditions in a generation. The year-to-date Palmer Drought Severity Index, which measures long term meteorological drought, is the lowest ever measured for California.
|The Palmer Drought Severity Index for California.|
Note the comparison with 1977!
As an admitted weather geek, I find myself devouring information about weather. I enjoy reading a blog called the California Weather Blog, written by Daniel Swain, a PhD student at Stanford. I frequently check the U.S. drought monitor website hosted by the University of Nebraska, Lincoln, which comes out with an updated drought map each Thursday. I've contributed information to the drought impact reporter, a site which allows public input to the drought monitor maps. And I've recently joined the Community Collaborative Rain Hail and Snow Network, a website that allows people to report on precipitation on a daily basis.
|All of California continues to experience drought conditions - and our region|
continues to experience the most severe drought conditions (despite the recent rainfall).
Beyond this high-tech interest in weather, I've kept a weather diary since 2001. I try to record the minimum and maximum temperature each day, along with the precipitation we've received during the previous 24 hours. I also try to track key climate related happenings - things like the first killing frost of the fall, the first time we build a fire in our wood stove, the first time I hear the sandhill cranes flying over in the spring and fall, when we first hear the tree frogs singing in the late winter, etc. I enjoy looking back and comparing the weather from one year to the next.
Increasingly, our weather in northern California seems erratic. During this drought, rainfall amounts have been strangely all over the board. Yesterday, for example, areas in the Sacramento Valley recorded more than a half-inch of precipitation, while we measured just 0.05 inches at home (typically, the foothills receive more rain than the valley floor due to orographic lifting (that is, as storms pass over higher elevations, more rainfall is "squeezed" out). Watching the Doppler radar yesterday, it looked like a band of heavy rain was moving into the foothills. Somehow it missed Auburn!
In "normal" years (whatever that means), we usually have a killing frost no later than the first week of November. For us, a killing frost means it gets cold enough (and stays cold enough) to kill the squash and tomato plants in our garden and knock the rest of the leaves off of our mulberry trees. Today is November 21, and we've yet to have a killing frost. If the weather forecast I just looked at is accurate, we won't have a killing frost for at least 7-10 more days. Very strange.
As I mentioned, I also record observations about wildlife in my weather diary. One of the most consistent wildlife mileposts in our area has always been the sandhill crane migration. Since 2001, I've heard cranes within a 3-4 day window in late September every autumn - the cranes seem to have calendars that tell them when to fly south. I might here and see the cranes going over for 10-14 days. This year's migration started at least 10 days later than normal (according to my notes) - and I heard them flying over up until last week. Also very strange.
From a ranching perspective, this autumn is shaping up to be better than last year. The springs, creeks and ponds that dried up last year are still dry, but at least we've had enough rainfall to germinate our grass and keep it growing. In this respect, the lack of a killing frost has been helpful - warmer air temperatures mean warmer soil temperatures. Hopefully we'll continue to grow grass until the shortening day lengths put our grasses into dormancy in early to mid December. Despite these improved forage conditions, however, we're still facing an increasingly serious crisis. After a year with very little snow pack in the Sierra Nevada, I'd hoped to see some snow during a day trip to Reno yesterday. There was very little snow on our way over in the morning, and while we did get some snow on the return trip, it didn't amount to much. This morning I heard that the upper reaches of Sugar Bowl Ski Resort received 3-4 inches from yesterday's storm. Earlier this week, the websites I look to for weather forecasts predicted that we'd receive as much as 1.5 inches of rain from the storm that's supposed to come in tonight. As of this afternoon, theses same sites are predicting less than a half an inch.
Increasingly, "normal" and "average" don't seem like useful terms for describing our weather - we seem to be entering a period where these terms apply to the midpoint between bouts of extreme weather rather than something we actually experience. For an obsessed weather geek and rancher like me, these extremes are fascinating to watch but troubling to live through.
|Hopefully we'll see more days like this in the near future - wet!|