LADWP snow surveys take place on February 1, March 1, and April 1 each year. LADWP hydrographer uses snow sampling tool to collect snow readings. Photos by Aqueduct Operations 2025. Cottonwood Snow Survey.

This month, our hydrographers trekked into the Eastern Sierra backcountry to conduct our annual snow surveys for this water year. With the completion of the Feb 1 snow survey, our hydrographers reported that, while conditions are still below average, they have improved. Additionally, another storm system may bring further precipitation to the Eastern Sierra this week. The surveys started Feb 1 and continue monthly through Apr 1. 

 As of February 11, 2025  

LADWP Eastern Sierra Current Precipitation Conditions reported:  

• 12.3” of water content 

• 76% of normal to date 

•54% normal of a typical water year ending April 1 

Snow surveying is carried out by skilled LADWP hydrographers, experts in snow sampling techniques, cross country travel, avalanche safety, first aid, and mountain survival. This work has a huge impact on shaping our water future by gathering important information that helps us better prepare for the year ahead.  

LADWP hydrographers use snow sampling tool to gather snow measurements. Snow samples are collected by using a "snow sampling set" consisting of a series of aluminum tubes about 1.5 inches in diameter and 30 inches long that can be screwed together. Photos by Aqueduct Operations 2025.

This century old practice, known as snow surveying, measures the depth of snow to determine its water content, helping predict runoff and provide an accurate water supply forecast. Snow depths are measured at four Eastern Sierra basins: Cottonwood Canyon, Big Pine Canyon, Rock Creek and Mammoth Pass. Markers are placed at specific locations and are regularly checked for snow levels and water content.

Snow surveying is especially crucial in the context of climate change, as climate becomes more unpredictable. It’s more important than ever to have reliable water forecasts to stay prepared and manage water resources for droughts and natural disasters. No snowpack is ever identical to the year before.  

When we keep an eye on the snow, we get a head start on making sure our water future is responsible and sustainable for the year to come!  

To view our full conditions report, click the button below and make sure to be a subscriber to our LADWP in the Eastern Sierra news to receive information directly to your inbox. 

Did You Know?

The practice of snow surveying adopted by LADWP hydrographer is more than 100 years old?!  

In 1925, Hydrographers from LADWP visited Dr. James Church to observe his techniques. Dr. Church of the University of Nevada at Reno began to measure snow in 1906 on Mount Rose to study the connection between the amount of snow on the ground and runoff. After their visit to Dr Church, LADWP crews took what they had learned and established snow courses and began regular snow surveys at four Eastern Sierra basins: Cottonwood Canyon, Big Pine Canyon, Rock Creek and Mammoth Pass. Today, these four locations continue to provide valuable data.