A historic winter season

Frank Gehrke, Chief Snow Surveyor for the Department of Water Resources at a snow survey last year.
Frank Gehrke, Chief Snow Surveyor for the Department of Water Resources at a snow survey last year. File Photo

Welcome news after five years of drought, the Sierra Nevada snowpack continues to build during one of the wettest winters in California’s recorded history, officials with the Department of Water Resources (DWR) announced last week.

The snowpack is close to setting records from more than three decades ago.

The manual snow survey by the DWR, taken March 1, at Phillips Station in the Sierra Nevada, found a snow water equivalent (SWE) of 43.4 inches. February’s Phillips survey found 28 inches of SWE, and January’s reading was 6 inches. The March 1 average at Phillips is 24.3 inches.

SWE is the depth of water that theoretically would result if the entire snowpack melted instantaneously. That measurement is more important than depth in evaluating the status of the snowpack. On average, the snowpack supplies about 30% of California’s water needs as it melts in the spring and early summer.

More telling than a survey at a single location are DWR’s electronic readings from 98 stations scattered throughout the Sierra Nevada. Statewide, the snowpack today holds 45.5 inches of SWE, or 185% of the March 1 average (24.6 inches).

Measurements indicate the water content of the northern Sierra snowpack is 39.2 inches, 159% of the multi-decade March 1 average. The central and southern Sierra readings are 49.0 inches (191% of average) and 46.4 inches (201%) respectively.

State Climatologist Michael Anderson said the winter season has been “historic,” especially in the central and southern Sierra where elevations are higher and where snowfall has neared the 1983 record amount.

The Phillips snow course, near the intersection of Highway 50 and Sierra-at-Tahoe Road, is one of hundreds surveyed manually throughout the winter. Manual measurements augment the electronic readings from about 100 sensors in the state’s mountains that provide a current snapshot of the water content in the snowpack.

Frank Gehrke, chief of the California Cooperative Snow Surveys Program, conducted the survey at Phillips.

“It’s not the record, the record being 56.4 (inches), but it’s still a pretty phenomenal snowpack,” Gehrke said. “January and February came in with some really quite phenomenal atmospheric river storms, many of which were cold enough to really boost the snowpack.”

Gehrke said the central and southern regions in the Sierra Nevada are tracking close to 1983, which had the maximum recorded snowpack statewide.

Many Californians continue to experience the effects of drought, and some Central Valley communities still depend on water tanks and bottled water. Groundwater – the source of at least a third of the supplies Californians use – will take much more than even an historically wet water year to be replenished in many areas.

California’s climate is the most variable of any state. Historically, it swings from drought to flood and back to drought. In addition, as global warming drives up average temperatures in California, more precipitation will fall as rain, not as snow stored in the Sierra Nevada and other mountains.

To help prepare for these ever-wider extremes, Californians can learn ways to save water every day by visiting SaveOurWater.com.