California Water Resources & Sierra Nevada Snow Survey
Report generated: 05/22/2012 12:04
| Summary By Section |
|---|
Section
|
|
Today |
Yesterday |
| NORTH | Number of Stations Reporting | 26 | 26 |
| Average snow water equivalent | 2" | 3" |
| Percent of April 1 Average | 8% | 10% |
| Percent of normal for this date | 22% | 26% |
| CENTRAL | Number of Stations Reporting | 39 | 39 |
| Average snow water equivalent | 1" | 1" |
| Percent of April 1 Average | 2% | 2% |
| Percent of normal for this date | 4% | 4% |
| SOUTH | Number of Stations Reporting | 29 | 28 |
| Average snow water equivalent | 0" | 0" |
| Percent of April 1 Average | 0% | 0% |
| Percent of normal for this date | 0% | 0% |
| Statewide Summary |
|---|
| Statewide Average SWEQ | 1" | 1" |
| Statewide Percent of April 1 | 3% | 4% |
| Statewide Percent of Normal | 7% | 8% |
Stations included in report:
North: (Trinity through Feather & Truckee) PET RRM BNK SHM MB3 HIG SCT MUM BFL CDP BLA SDF MED
ADM SNM SLT STM KTL GRZ PLP GOL HMB RTL BKL FOR NLS
DSS IDP BMW SQV IDC INN TK2 LLP | | Central: (Yuba & Tahoe through Merced & Walker) LOS SCN CAP ALP MDW SIL CSL HYS VVL RBB GKS BLC RBP
DDM HHM GNL REL BLK MDL SLM BLD BLS DAN SLI TNY TUM
HRS STR PDS GIN KIB MSK HVN HGM MRL EP5 RP2 TCC WC3
FLL EBB PSN MNT SPT LVT VRG LBD SPS LVM CXS HOR BSK
FDC SDW RCC WHW | | South: (San Joaquin & Mono through Kern) VLC AGP KSP GRM TMR CHM HNT GRV PSR BSH CRL STL MTM
BCB UBC WWC BIM QUA GNF UTY CBT CHP PSC TUN WTM CSV
BCH GEM SWM CWD BGP SLK MHP RCK FRW DPO |
Hydrologic Conditions in California (05/01/2012)
| Northern Sierra Precipitation Accumulation (1) |
|---|
Rainfall & Snow Water Content (in inches)
|
|
| Water Year Amount to Date (since Oct. 1, 2011): | 39.70 |
| Average to Date: | 45.50 |
| Percent of Average to Date: | 87 % |
| Average for the Water Year (Oct. 1 through Sep. 30) | 50.00 |
| Percent of Average for the Water Year (Oct. 1 through Sep. 30) | 79 % |
| (1) | Northern Sierra (Sacramento, Feather, Yuba, and American River Basins)
|
| Snowpack Water Content |
|---|
Region
|
Water Content
(in inches) |
%
Avg to Date |
%
April 1 Avg (2) |
| Northern Sierra | 15.80 | 77 | 56 |
| Central Sierra | 9.40 | 37 | 30 |
| Southern Sierra | 4.40 | 21 | 17 |
| Statewide | 9.70 | 43 | 34 |
| (2) | April 1 is the date of normal maximum accumulation for the season.
|
| Forecast of Regional Water Supply Indices (3) |
|---|
| Index |
Value |
Year Type |
| 8 River Index for April (in 1000 AF) | 3,700 | n/a |
| Sacramento Valley Water Year Type Index (40-30-30) @ 50% | 6.9 | Below Normal |
| Sacramento Valley Water Year Type Index (40-30-30) @ 90% | 6.6 | Below Normal |
| San Joaquin Valley Water Year Type Index (60-20-20) @ 50% | 2.3 | Dry |
| San Joaquin Valley Water Year Type Index (60-20-20) @ 75% | 2.2 | Dry |
| (3) | For more information see Sacramento & San Joaquin Valley Water Year Type Index forecast: Latest | Previous
(Issued monthly from December 1 through May 1) |
| Key Reservoir Storage As of 03/31/2011 midnight |
|---|
| Reservoir |
River |
Storage
(in 1000 AF) |
Avg Storage
(in 1000 AF) |
%
Average |
Capacity
(in 1000 AF) |
%
Capacity |
Flood Control (4)
Encroachment
(in 1000 AF) |
| Trinity Lake | Trinity | 2,338 | 2,049
| 114 | 2,448 | 96 | --- |
| Shasta Lake | Sacramento | 4,440 | 3,974
| 112 | 4,552 | 98 | -112 |
| Lake Oroville | Feather | 3,422 | 2,939
| 116 | 3,538 | 97 | 139 |
| New Bullards Bar Res | Yuba | 930 | 760
| 122 | 966 | 96 | 34 |
| Folsom Lake | American | 933 | 730
| 128 | 977 | 96 | 131 |
| New Melones Res | Stanislaus | 1,945 | 1,482
| 131 | 2,420 | 80 | -281 |
| Don Pedro Res | Tuolumne | 1,652 | 1,470
| 112 | 2,030 | 81 | -65 |
| Lake McClure | Merced | 773 | 612
| 126 | 1,025 | 75 | -77 |
| Millerton Lake | San Joaquin | 370 | 365
| 101 | 520 | 71 | -150 |
| Pine Flat Res | Kings | 744 | 610
| 122 | 1,000 | 74 | -256 |
| Isabella | Kern | 201 | 224
| 90 | 568 | 35 | -160 |
| San Luis Res | (Offstream) | 1,647 | 1,861
| 88 | 2,039 | 81 | --- |
| (4) |
Temporary encroachment into seasonally reserved flood storage space; requirements can vary considerably on a daily basis
due to numerous variables: rainfall amounts, anticipated snowmelt, time of year, soil moisture, etc.
|
| Selected Cities Precipitation Accumulation As of 04/30/2012 |
|---|
| |
Jul 1 to Date
2011 - 2012
(in inches) |
%
Avg |
Jul 1 to Date
2010 - 2011
(in inches) |
%
Avg |
% Avg
Jul 1 to Jun 30
2011 - 2012 |
| Eureka | 38.02 | 101 | 42.41 | 112 | 94 |
| Redding | 22.75 | 71 | 31.02 | 97 | 66 |
| Sacramento | 12.18 | 69 | 21.46 | 122 | 66 |
| San Francisco | 15.58 | 68 | 25.75 | 113 | 66 |
| Fresno | 8.15 | 75 | 15.25 | 140 | 71 |
| Bakersfield | 4.93 | 79 | 10.02 | 161 | 76 |
| Los Angeles | 7.60 | 61 | 17.30 | 138 | 59 |
| San Diego | 8.01 | 79 | 12.23 | 120 | 77 |
| Comments |
|---|
| As of April 30, statewide hydrologic conditions were as follows: precipitation, 75 percent of average to date; runoff, 65 percent of average to date; snow water equivalent, 40 percent of average for the date (30 percent of the April 1 average); and reservoir storage, 115 percent of average for the date. Sacramento River Region unimpaired runoff observed through April 30, 2012 was about 8.5 million acre-feet (MAF), which is about 64 percent of average. For comparison, on April 30, 2011, the observed Sacramento River Region unimpaired runoff through that date was about 16.5 MAF, or about 124 percent of average.
Precipitation in April was generally above average or near average across California. On April 30, the Northern Sierra 8-Station Precipitation Index Water Year total was 39.7 inches, which is about 87 percent of the seasonal average to date and 79 percent of an average water year (50.0 inches). During April, the total precipitation for the 8-Stations was 6.5 inches, which is about 167 percent of the monthly average. Last year on April 30, the seasonal total for the 8-Stations was 64.3 inches, or about 141 percent of average for the date.
On April 30, the San Joaquin 5-Station Precipitation Index Water Year total was 24.0 inches, which is about 65 percent of the seasonal average to date and 59 percent of an average water year (40.8 inches). During April, the total precipitation for the 5-Stations was 4.8 inches, which is about 137 percent of the monthly average. Last year on April 30, the seasonal total for the 5-Stations to date was 57.7 inches, or about 156 percent of average for the date.
The latest National Weather Service Climate Prediction Center (CPC) long-range, 1-month precipitation outlook for May 2012, issued April 30, 2012, suggests below average precipitation for Northern and Central California. The outlook suggests no tendency for above or below average rainfall for the southern part of the State.
Updates to the Executive Summary will generally be issued approximately weekly, biweekly, or monthly (depending on conditions) through the wet months of winter and spring. Beginning about June 1, this product is updated monthly through the dry seasons of summer and fall. The next update of this product will be issued about Monday, June 11, 2012, unless there are significant hydrologic changes.
|
|
