— from Paul Kamin, Eastsound Water —
The Seattle area experienced record rainfall in October. Over 9”, more than double the 3.5” average.
On Orcas, rain was recorded on all but a handful of days last month, but our 6.5” of rainfall did not break any records. Below is a chart of the rainfall Eastsound Water recorded last month, compared to previous Octobers.
October is a month of rather high rainfall variability. October can be an extension of the dry summer season, or it can be the beginning of the wet winter season. [Below] is a graph of the last 16 years of October precipitation records collected by Eastsound Water.
You might suspect that with a wet October our Purdue Reservoir has begun refilling rather rapidly. Indeed over the month of October the lake gained 1 ft, (from 13.5 ft to 14.5 ft.), and the lake level is slightly higher than “normal” at this time of year.
Eastsound Water staff measured almost 7” of rainfall at Purdue, but that much rain, falling on 385 acres of uphill terrain [should have] a much larger impact on the water level in our 11 acre reservoir.
However, every fall there is a significant “delayed reaction” when it comes to refilling the reservoir. Most of October’s precipitation was “absorbed” by the dry ground in our forests and very little ended up “running off” into the lake. Over November and December the water level in Purdue will hopefully gain another 5.5’ and begin overflowing.
Thanks Paul. This is interesting stuff.
Rain, rain, rain………….. Bring it on. Love it. When I moved from Sitka, AK to Orcas Island (one beautiful place to another)it was not unusual in Sitka to receive an inch of rain a day in October. There is more daylight here though.
It’s interesting how much the precipitation varies here in the islands. Not unusual for there to be no rain in some locations and a fair amount in others. There are several people here that report daily precipitation to a site called “Cocorahs” and you can view the daily maps with each reporting station shown and also view historical data from each station.
We live on the north side of Mtn. Constitution (1700′ up); rain for the year is 12.55″, for Nov. 3.51″ already and 7.75″ for October. Always glad for rain not snow this time of the year.
Mike- Your YTD precip seems way low, we have had 23″ here on north end of Blakely.
There is always the chance the electronic rain gauge is plugged with pine needles, but I do not think so. The numbers agree with the old fashion glass gauge you read manually. We are slightly below the ridge and protected somewhat from storms off the Pacific. Also we are only slightly ahead of last year’s at this time. The microclimates on these islands are pretty severe. Its probably just location – location – location. By the way, the rain year runs August to August.