LAKE COUNTY, Calif. – With little rain this fall and early winter, Clear Lake earlier this month hit the lowest level in four years.
On Dec. 21, 25 and 26, Clear Lake’s level was recorded as 0.62 feet Rumsey, the lowest depth for the lake recorded since Dec. 12, 2009, based on records available online from Lake County Water Resources and the US Geological Survey.
Rumsey is the special measure used for recording the depth of Clear Lake. Zero Rumsey is equivalent to 1318.256 feet.
According to the Lake County Water Resources Web site, “The natural level of Clear Lake has been maintained by the Grigsby Riffle, which is a rock sill located at the confluence of Cache and Seigler Creeks near Lower Lake. The natural low water level of Clear Lake was established as 'Zero Rumsey' and all subsequent lake measurements are based on this elevation.”
November and December of 2009 saw slightly lower lake levels than this month, registering numbers not matched in available online records going back to 2001.
The lake's deepest measurement for this year was 6.23 feet Rumsey, recorded April 5-6.
The deepest measurement for the lake since 2001 was 9.37 feet Rumsey, recorded on March 28, 2011, when the county was hit by rains and flooding.
The lake level on Dec. 26 was the lowest recorded for that exact date over the last 12 years.
Usually by late December the lake already has started to fill up thanks to fall and winter rains. But that has not been the case this year.
On that same date last year the lake was measured at its highest level for that same date since 2001; on Dec. 26, 2012, the lake was at 5.84 feet Rumsey.
Clear Lake's levels on Dec. 26 going back to 2001 are as follows, according to Lake County Water Resources:
- 2013 – 0.62;
- 2012 – 5.84;
- 2011 – 2.89;
- 2010 – 4.22;
- 2009 – 0.70;
- 2008 – 1.15;
- 2007 – 1.20;
- 2006 – 3.17;
- 2005 – 4.84;
- 2004 – 1.89;
- 2003 – 4.26;
- 2002 – 4.63;
- 2001 – 3.78.
Based on Lake County Water Resources records, the extremes for Clear Lake since consistent monitoring began in 1913 include a high of 11.44 feet Rumsey on Feb. 24, 1998, a year that saw major flooding in the county.
On the other end of the spectrum, the lowest lake level since 1913 was -3.50 feet Rumsey, which was recorded Sept. 24-27, 1920.
As for the chances for a wet winter, the National Oceanic and Atmospheric Administration's US Seasonal Drought Outlook, released Dec. 19, expects drought conditions to persist or intensify over most of California, including Lake County.
Correction: The story previously had said a reading of 0.01 feet Rumsey reported on Dec. 6 was the lowest since 2001. That US Geological Survey reading was an error, according to Lake County Water Resources, with the actual reading for that day being 0.69 feet Rumsey. While records show that at various times over this month the depth has dipped below 0.60 feet Rumsey, averages were slightly higher than the December 2009 levels.
Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it. . Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.