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Shasta Update Oct 27

Posted: Wed Oct 27, 2021 8:00 pm
by WB Staff
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Muddy waters after the rain. Holiday Harbor is in the center of the picture.

From Shasta Lake

Good afternoon Shasta Lake!
The lake has not only stabilized, but it has shot up a few feet from where we bottomed out this year. From October 21, 9pm to midnight of October 22 (3 hours), CDEC reported an elevation of 882.24 ft, or 184.86 feet down from full pool. In comparison, we were very close to 2014 elevation when we bottomed out around 177 feet down.
Interesting information about the recent storms:
- Highest recorded rainfall at the McCloud location - 5.34" (10/22)
-Highest inflow was 53,864 cubic feet per second (6am, 10/22)
-The lake has jumped up 3.78 ft from it's low.
It is how the storms arrived that has made the unique impact from these storms. Usually it will take several events of rain before the ground is saturated enough to allow run-off and "sheeting" to take place. This year, it happened on the first event. The amount of heavy and steady rain certainly saturated the top soil and even further. So much so that it is raining in Lake Shasta Caverns, you can hear the amount percolating through the mountain in the video.
With the hydrology back in action on the lake, it promotes other obstacles. The fine silt has turned into a slick mud encasing the majority of the shoreline. The mud is pulled towards the lake through erosion and ends up in the lake. The turbidity of the lake continues to turn the silt & water mixture into what looks like chocolate milk. Some of these valleys have potential for large mudslides, moving hundreds of yards of material in minutes during our deluges.
What I will point out as an interesting observation is to why the powers that be, were releasing water from the dam almost at the same rate as the inflow. This helps to explain why Oroville jumped 12 feet and Shasta only 4. I have not heard any explanation for this yet, but everyone on the lake is wondering why that happened.
While this creates a muddy, and almost impossible mess to work in, you can rest assured that the lake is very busy with employees keeping the docks, boats and other infrastructure safe. Yet we are loving every single drop that falls and fills the lake.
Keep those rain dances up and BRING ON THAT RAIN!!!
Lake Level Report (10/27/2021 at 12:00 hrs)
Lake Elevation: 885.73' (181.08' below full pool)
24 Hour Difference: (UP) +0.27'
Lake Elevation (2020): 962.75' (104.25' below full pool)
Storage: 1,271,310 af (estimated)
Storage (2020): 2,095,094 af
Outflow (24 hr avg): 4,851 cfs
Inflow (24 hr avg): 6,657 cfs
Total Capacity: 22%
Historical Average: 41%
Precipitation (24 hr @ McCloud): 0.06"
Precipitation (Season @ Dam): 7.89"
Precipitation (2019-2020 Season @ dam): 0.20"