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Thursday, April 13, 2017

Five Feet of Rain

Yearling ewes and lambs - enjoying a little sunshine this evening
When I got home this evening, we'd measured 0.79 inches of rain since 7 a.m. - it's since rained (and hailed even more). For the month of April, we've measured 5.57 inches so far - making April 2017 wetter than March. Most impressively, we've surpassed 60 inches of rain for the season (since October 1, 2016) - almost twice our average annual rainfall. We've had enough rain, finally, that California Governor Jerry Brown declared an end to our drought. But even in this record setting year, we seem to be seeing the lingering effects of the driest (and hottest) stretch in the last 500 years.

The National Centers for Environmental Information (part of the National Oceanic and Atmospheric Administration) posted an article this week about the continuing impacts of California's drought. The post, which summarizes a longer paper from the Journal of Climate, suggests that it may take some parts of California decades to recover from this particular dry spell. For the full article, click here.

My observations haven't been scientifically rigorous, but they do suggest that there's something to the idea that a single wet year won't result in a full recovery. For example, we've had 15 inches more rain this season than we measured in the next wettest year since we've lived in Auburn. Even so, we haven't had standing water in our pastures for more than a day or two until this week. The seasonal creeks that flow through our winter grazing land seemed to flow for a week or so after particularly heavy rains - but then they'd quit. Much of the rain seems to have soaked in rather than run off - a good thing for groundwater supplies! Nonetheless, these phenomena suggest that we had a huge moisture deficit.

Part of what made this most recent drought unique were the unusually warm winter temperatures we experienced. During several dry winters, some of our deciduous oaks never lost their leaves. Many of our annual grass species matured earlier than normal. This winter, while the high Sierra received record amounts of snow, the mid elevations (4,000 to 5,500 feet above sea level) seemed to be mostly free of snow when I traveled through the mountains.

Climate scientists suggest that we'll likely experience more extreme weather events as the climate continues to change. Since October 1, 2016, we've had 24 instances in which we measured more than 1 inch of rain in a 24-hour period. I'd have to go back through my weather journal, but I suspect that this is unusual for Auburn. November 2016 was unusually warm; April 2017 seems unusually wet (so far, we've had nearly twice our normal April rainfall). The article I cited above indicates that "higher temperatures could combine with and amplify severe precipitation deficits." Extremes, I guess, might be the new normal.

Regardless of what the future climate brings us, we're awfully wet here in Auburn. I guess 60 inches of rain in a region that normally gets 30 inches will do that! As we sold two-thirds of our sheep during the drought, I swore I'd never complain about rain again - and I'm not complaining now! That said, I certainly enjoy the sunshine when it returns!

2 comments:

  1. 26.00" at the Snow Ranch as of 4/14/2017. Not a record but very much appreciated after the last 5 years.

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