Happy start of the rainy season in Seattle! Sure, it's blazing sunshine of late again, but Oct. 1 is the official start and thus also marks the start/end point of the "water year."
In addition to tracking rainfall from Jan. 1 to Dec. 31, NOAA also tracks it from Oct. 1 to Sept. 30 (calling it the "water year" rainfall) since our rainy season goes from October to March, this way we can also get a good gauge of the autumn/winter as a whole and its impact on our water and snowpack situations.
For 2014-15, Seattle ended up with 36.82 inches of rain, just 2/3" below the normal of 37.49 inches.
But this year, it'd be real nice if "rainy season" lived up to its title, since our drought is still going stong.
Now some are probably wondering: "Wait a minute, but you just said we weren't that far below normal for our past 'water year', how can it be a drought?" Indeed, last year we had about 39.11" for our 2013-14 water year -- just a little more than 2" than this year -- and we weren't in this bad of shape.
How is that possible? There are a few issues in play:
1. Much of last autumn and winter had warm, heavy rains that counted quite a bit in the official rain gauge in Seattle, but with little mountain snow to establish any kind of "water bank" for our region to draw off in the summer.
2. In addition, most of the rest of our rain this year also came in heavy spurts -- especially in late winter and August. It's better to have lighter rains spread out over greater days than heavier rains in a punch that allows some of the water to run off and not be absorbed. While our total rainfall is somewhat near normal, the number of rainy days so far this year is below normal.
3. Late winter through spring and into mid summer were very dry across the state with several extended periods with no rain.
4. It's been much hotter than normal -- several sites have smashed temperature records by leaps and bounds this year -- and that causes more rapid evaporation and decreasing soil moisture content. Because it was so hot and dry for so long, and we didn't have a winter snowpack to draw from, aquifers and reservoirs that supply water to fish, farms and communities across the state took a major hit, according to the Washington Department of Ecology.
As it stands, even with the two rainy storms in August, we've gone back to a drier than normal September, leaving Western Washington in "severe drought" wihile Eastern Washington remains in the "extreme drought" category.
Officials say we need a normal snowpack year to avoid a second year of drought, but it's not looking good as with a strong El Nino in play for this upcoming winter, all signs point to another drier and warmer season with a lower than normal snowpack expected.
For More Information:
Washington Department of Ecology Drought page
Dept. of Ecology interactive drought "tour"