California Snow Survey Measurement Schedule

Preface

This measurement schedule is prepared for agencies participating in the California Cooperative Snow Surveys Program. Cooperating agencies are urged to make their measurements as close to the first of the indicated month as possible. Specifically, the measurements should be made within a period of no more than seven days before the first of the month or two days after the first. For example, the February surveys should be made between January 25 and February 3. Timely data is required to complete water supply forecasts and publish Bulletin 120, "Water Conditions in California."

Measurements are made in conformity with snow course maps issued by the Snow Surveys Program. Omissions, errors, or changes in site conditions at snow courses may exist. Information or corrections should be forwarded to California Cooperative Snow Surveys, Department of Water Resources, P.O. Box 219000, Sacramento, CA 95821-9000, or call (916) 574-2636.

The "California Number" uniquely identifies every snow course and automatic snow sensor. The numbering system began in 1949 by assigning consecutive numbers from high to low elevations within each watershed and moving from north to south within the State. New installations since then have been assigned consecutive numbers regardless of their location. Snow courses are assigned numbers from 1 through 499. Aerial snow markers installed during the 1960's and no longer utilized were assigned numbers between 500 and 599. Automatic snow sensors located within approximately 100 yards of a snow course share the same number as that snow course. Automatic snow sensors located near an aerial snow marker are assigned the 500 series number. If snow sensors are located more than 100 yards from a snow course or aerial marker they are assigned numbers from 800 to 899. A "W" following any number means that site is located within the U.S.D.A. Forest Service National Wilderness Preservation System.

This report contains an average April 1 water equivalent for snow courses computed for the 50-year period 1951 through 2000. Sites with less than 50 years of record have averages computed based on the entire period of record. Averages reflect corrections to the historic record and are subject to revision.

TABLE 1 lists all the cooperating AGENCIES making snow survey field measurements in California with their respective two-digit code numbers.

TABLE 2 lists all the active snow courses to be measured this year arranged by DRAINAGE BASIN. TABLE 4 lists the snow courses arranged by MEASURING AGENCY code number. TABLE 5 lists all the DISCONTINUED snow courses by drainage basin for which an historical record exists.

TABLE 3 lists all automatic SNOW SENSORS to be ground checked and is arranged by drainage basin. Manual snow tube measurements at each sensor site are made in accordance with site maps available from the Snow Surveys Program office. Control samples should be reported on a separate snow course note form, including manometer or temperature readings at sites where manometers or thermometers are present.