March 16,2023,6AM
Southern Sierra has biggest snowpack ever
MORE COMING
NWS says next week expect more rain events ( see map end of story)
The Southern Sierra now has the largest snowpack in recorded history (as measured by snow water equivalent, or SWE). Not just for March 15, but any time. As of press time, snowpack is 271% of normal and 260% of April 1 average.
Amply supplied by multiple warm atmospheric river storms, as of now all creeks and rivers are heading for the Tulare Lake Basin propelled by gravity. Flows are evident from Deer Creek to the Tule River and from the Kaweah – all with more volume than can be handled in the eastern part of the Valley.
That includes flows from the Kaweah River says Mark Larsen who heads up the Kaweah Delta Water Conservation District. ”These storms have been huge events” and water from the Kaweah” has been heading to the lakebed for some time now”.
Larsen says he expects Kaweah Lake to fill with storm runoff “in the next 24 hours.” The question will be – how much does it spill?”
UPDATE: Kaweah Lake fills
As of March 16 at 6AM both dams have filled in a matter of 6 days -the result of two vigorous Atmospheric River events where warm temps helped the rain melt snow at high elevations.
Kaweah Lake(Terminus Dam) went from 50,000AF to 185,000AF from March 10 to March 16. That’s full. Lake Success went from 25,000AF to 98,000AF- more than full- in 6 days.
“So far it is only part of King County to be impacted is in the south part of the county” in the Corcoran area where “we have problem but the Boswell people are managing most of the flood flows” says Kings County Supervisor Doug Verboon.
On the Tule, the Schafer Dam on Lake Success has been spilling since Saturday as the lake is full and more is coming every hour.The volume of the spill is increasing as the sheriff is ordering evacuation of residents in the area.
Flows has impacted areas along Highway 99 at Earlimart and Teviston as the water heads west.
As far as the northern part of the county so far the Corp of Engineers is handling flows on Kings River from Pine Flat Dam. For a while, releases from the dam were halted temporarily to allow for the tributary Mill;Creek to flow and fill the riverbed but now those flows have died down. The Corps is again releasing water from of the dam to make room for continued high runoff into Pine Flat.
So far the Corps has managed the water to keep it out of the lake bed believes Verboon so as to not to compound what is coming from the Kaweah and Tule from the south he says.”They are doing a good job” but for how long?
Bigger problems
Even as this week’s storm is abating, Kings River watermaster Steve Haugen notes that we will likely have considerably bigger potential problems in the future.
“What we’ve gone through is just the beginning,” Haugen said.
“We can expect these large amounts of Kings River flows or more for the rest of the season.” The series of potent storms since Christmas has created—despite recent warm rains to fairly high elevations—what may be the biggest Kings River watershed snowpack ever observed.
At least one agency is predicting April through July peak season runoff to Pine Flat Reservoir is likely to be near or above all-time record runoff amounts. Those marks were established in 1983.
Kings River flows into Pine Flat Reservoir were very high during the recent storm event but Haugen said the inflow has been steadily dropping.
The reservoir is likely to reach 800,000AF by Friday March 17 -The reservoir can hold 1 million acre feet.
Rainfall amounts in Giant Forest
One measure of the latest storm that ended March 15 is look at one Kaweah weather station at 6500ft – Giant Forest.
First note that the weather station has gained about 26 inches of rain since late February now totaling nearly 80 inches for the water year -probably close to a record
As of March 12, the warm storm that caused the most havoc with heavy runoff in the region where Giant Forest was hit with about 15 inches was from March 10 -12! Lots of that high elevation rain melted the snow and it came down the Kaweah River to help fill Terminus Dam this week.
Source says some rain fell at the top of the Sierra at 10,000 feet!
Then on March 14 in the second rain event – Giant Forest-received 6 inches – not as much as the previous warmer storm.
The impact has been at least so far today (10:30AM), there is less runoff into the lake as we gear up for a well-deserved break in this crazy weather for a few days.
However the NWS Hanford is predicting another 4 to 6 inches next week in the Southern Sierra. Here is the latest map.
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