Measuring the Impact of a Record Snowpack
Measuring the Impact of a Record Snowpack
The stillness stretches for miles in every direction at the highest peaks of the snow-capped Sierra Nevada. Back-to-back atmospheric rivers that pummeled California since the first days of the new year have accumulated into a historic snowpack, creating beautiful scenery the Sierra has not seen for many years. Below the untouched powder lies both opportunity and challenges.
“We live in an incredible place,” said Matthew Paruolo, Southern California Edison Government Relations manager based in the Eastern Sierra. “There are incredible advantages to living here, but we also have complexities that don’t exist in urban or lower elevation areas.”
In Mono County, located at one of the highest elevations in the country, homes and critical roadways disappeared under 20 to 30 feet of snow, with entire communities becoming inaccessible for days and residents unable to dig out from the snow. For SCE crews, power outages due to the severe weather and avalanches demanded speed, safety and teamwork to provide customers with electricity, water and life-saving services.
“We were also able to quickly get our crews into our Lundy Hydroelectric Powerhouse and deploy backup generators to bring our customers back online. We’re continuing to operate under these configurations while conditions stabilize, allowing our crews to plow access to avalanche zones and safely repair the damage.”
With weather conditions stabilizing, SCE crews are soon expected to restore regular grid operations, while the snow will continue to impact California for many months, at a minimum.
Between breaks from the heavy snowfall, SCE’s Air Operations helicopter has been scaling the Sierra Nevada carrying a small team of hydrographers with a big task. Hydrographers determine how much water the snowpack will produce when it melts as temperatures warm. That water flows into rivers, lakes and reservoirs, keeping water districts, farms and recreation afloat, and generating renewable hydroelectric power for customers on its way downstream. This year, it’s expected to flow in abundance.
“I’ve never seen anything like this,” said Derrick Tito, SCE foreman and hydrographer, who has measured the snowpack for 21 years. “The snow keeps coming. It’s not a bad thing, it’s natural, but it presents some challenges.”
SCE, other utilities and water districts contribute to the California Data Exchange Center, measuring the snow’s density across the Sierra to reveal the state’s projected water supply. To produce this data, hydrographers drill deep into the core of the snowpack to weigh a section of snow. Normally a relatively simple process, this year’s massive snowpack forced hydrographers to get creative to reach the bottom.
“We maxed out our scales,” Tito said. “Our hydrographer Jeff Sherman had the great idea to use a five-gallon bucket and place all the cores in the bucket to weigh them, and that worked fantastic.”
The results have been astounding. SCE’s snowpack measurements have ranged from 190% to 432% of average — statewide it stood at 239% on April 1. These numbers equate to water content not seen in the last 50 years — and that could be a problem.
While the winter storms have helped pull California out of extreme drought, the resulting snowpack and inevitable melt pose serious risks of flooding.
“In normal years, the surveys are about how you’re going to use the limited resources you have, like in previous dry years,” Tito said. “This year, we have more water than we can use. These numbers help water managers, as well as FEMA, prepare for what could potentially happen the rest of the year.”
The excess water is already inundating the San Joaquin Valley, where farms are submerged under a resurfacing Tulare Lake and once-dry river streams are now filled to the brim. Local governments are preparing for the possible long-term effects of the runoff. SCE’s operations are equipped to manage high volumes of incoming water, should the snowmelt persist into the following winter season.
“We are reducing water levels in our reservoirs to effectively manage capacity and the flow of projected natural snowmelt runoff. Though we are anticipating increased water flows into and out of our reservoirs, we do not believe these flows will pose significant dam safety risks,” Paruolo said. “The safety of our employees, contractors and communities are our number one priority.”
To learn more about SCE's hydroelectric power operations, visit on.sce.com/big-creek.