Snow Surveys

Sunset over French Lake

Every snowflake counts

NID conducts snow surveys during winter and spring months along six courses in the Sierra Nevada, which is the source of water for our customers.

The measurements of mountain snow depth and water content help our experts to make informed water-planning decisions.

Latest Survey – March 2020: 46 percent of average for water content; reservoirs are near average for this time of year as water management tightens

Click here to read the survey

February survey – snowpack water content below average, reservoir storage above average. Click here to read.

An NID surveyor takes measurements in 1926

NID collects water from snow on 70,000 acres of high Sierra Nevada watersheds. The District holds valuable water rights to these supplies and does not have to purchase water from other agencies. That means every snowflake counts as an important drop in our community’s water supply.

NID has been keeping snowfall records for more than nine decades. Today, our hydrologists trek up to the snow to take measurements during the winter and spring months.

In the early days, surveyors depended on skis and snowshoes to get to take snow courses. These days, our hydrologists use a helicopter to reach the higher elevations.


NID tracks the snowpack on six different snow courses:

* Webber Peak (7,800- foot elevation)
* English Mountain snow course (7,100 ft.)
* Webber Lake (7,000 ft.)
* Findley Peak (6,500 ft.)
* Bowman Reservoir (5,563 ft.)
* Chalk Bluff (4,850 feet on the Deer Creek watershed)

NID’s historic primary course is at Bowman Reservoir (elev. 5,650 ft.). The 69.2-inch annual average precipitation at Bowman compares to an annual average of 56 inches at 2,700 feet near Nevada City and 52 inches at 2,400 feet in Grass Valley.

Upper snow courses

Besides keeping records to use by the District, NID is a participant in the California Cooperative Snow Survey Project. Established in 1929, the program includes more than 50 state, federal, and other agencies, which collect, analyze and share snow data from more than 265 snow courses and 130 snow sensors located throughout the Sierra Nevada and Shasta-Trinity mountains. The findings help forecast seasonal and water year runoff for local areas and the state.