When California water officials announced earlier this month that the amount of snow in the Sierra Nevada was less than any measurement ever before recorded on that date in state history, it came as no surprise to a team of Jet Propulsion Laboratory scientists.
They had been watching the diminishing snowpack every week for three seasons in a row — from the vantage point of a specially equipped plane flying above the vast mountain range.
But their experience monitoring the dry winters as part of an innovative snow-science mission didn’t make the reality of the statistic — which showed that snowpack was at 5 percent of normal for April 1 — any less dismaying.
"This is definitely the worst I have seen," said Jeff Deems, a research scientist at the National Snow and Ice Data Center. "I've been coming to the Sierras ever since I was a little boy and I remember summer backpacking trips that had more snow ... . It’s really bad out here."
Deems is a key member of the team that runs the Airborne Snow Observatory, which uses newly available technology to take measurements from a small fixed-wing plane, revealing the amount of water available in the mountains.
Deems, who is based at the University of Colorado, Boulder, earlier this month oversaw a team measuring snowpack in the field near Lake Mary, a few miles from Mammoth Lakes. The team worked near what is normally a groomed cross-country ski trail, part of one of California’s premier ski resorts, Mammoth Mountain.
Instead of being packed with snow, the road was mostly pavement.
"All of the south-facing slopes are bare," Deems said. "The only snow is on the high-elevation north-facing slopes."
Deems and his team were taking ground snow measurements to validate the data from the plane flying overhead. On this particular day in mid-April, Deems’ group had trouble even finding a flat patch of snow large enough to take meaningful measurements, despite a trek made well into the wilderness.
The Airborne Snow Observatory pilot project is funded — to the tune of about $1.2 million annually — by NASA and the California Department of Water Resources, which is eager for the data. The project is based at JPL in La Cañada Flintridge.
Since it was launched in 2013, the mission has gained increasing attention as snowpack has declined amid the state's worst drought on record. Now faced with the first mandatory water-use cutbacks in state history, Californians are being told that every drop matters.
The Airborne Snow Observatory's new technology is able to show just how many drops there are left — pretty much exactly.
That's information wanted by water officials, farmers and politicians alike because the Sierra Nevada provides between one-third and two-thirds of the state's closely watched fresh water supply.
"Snow really anchors the water resource, which itself anchors the civilization, the infrastructure, the ability to have the industry we have, the agriculture that we have, the huge populations that we have," said Tom Painter, a JPL scientist who founded the Airborne Snow Observatory.
Painter's project uses lasers that fire off 800,000 times per second from the bottom of a Beechcraft King Air A90 aircraft that flies over the Sierra out of Mammoth Yosemite Airport.
The mission combines a scanning LIDAR system with an imaging spectrometer to get data about snow's depth, water content and, essentially, its whiteness, which corresponds to how fast it will melt. Ground measurements taken by Deems' team support the work in the air.
Frank Gehrke, chief of the California Cooperative Snow Surveys program for the Department of Water Resources, has known Painter for some two decades and now works with him on the Airborne Snow Observatory.
The project obtains the "holy grail of snow hydrology" by providing scientists and water managers with the exact water content of the snowpack over very broad areas, Gehrke said. The mission is made even more successful by the fact that the data is available within 24 hours, giving water managers a nearly instant picture of how much water will be coming down from the mountains in spring, running into reservoirs and rivers.
"It’s pretty revolutionary," said Gehrke, who has been doing snow surveys for California since 1981. "The technology provides so much information that we didn’t have before."
The measurement of snowpack isn't new -- the state has been doing it for more than 100 years. But never before has the data been so thorough and accurate.
Winter ritual in California: monthly 'manual survey'
Since 1909, scientists have sunk large, hollow metal cylinders into the snow, weighing the core of snow that gets packed inside to determine how much water it holds.
The "manual survey" -- done monthly in winter and spring, sometimes before reporters and television news crews -- has evolved and expanded to use new technology over the years.
But one blind spot has always been that the highest measurement site available to California water officials was at an elevation of 11,350 feet -- in a mountain range that includes the highest peak in North America, Mount Whitney, at 14,505 feet.
That left officials essentially guessing how much snow was available at the higher elevations. Now the Airborne Snow Observatory can take those high-altitude measurements from thousands of feet overhead.
Painter compares the old method to having only a few pixels filled in on a screen. The Airborne Snow Observatory, he says, can fill in every single pixel.
"If you don't know how much actual snow there is, you don't know how much water there is," Painter said.
Low snowpack a dramatic marker of drought
On April 1, Gehrke stood by Gov. Jerry Brown in the community of Phillips, between Sacramento and Lake Tahoe, where the site of longtime a manual snow survey stood bare for the first time on that date in 75 years.
On average, the Phillips snow course has about 5 1/2 feet of snow on April 1.
With the point made partly by his snowless surroundings, Brown took the opportunity to announce his executive order mandating a 25 percent reduction in water use for urban Californians.
"This is the new normal," Brown said.
That same day, Airborne Snow Observatory data announced by JPL showed the Tuolumne River basin -- which quenches San Francisco's thirst -- had 40 percent as much water as it did in 2014, already one of the two driest years in state history.
State water board Chairwoman Felicia Marcus said the state has seen dry years before, but the series of several dry winters combined with high temperatures and "no snowpack to speak of" made this one extraordinarily difficult.
Previous severe droughts came when the state's population was much smaller, she said.
"California’s drought is unprecedented," Marcus said. "The impact of this is far greater since … we have millions more people."
The board is expected early next month to approve a measure requiring communities across the state to cut back between 8 and 36 percent of their water use in order to meet Brown's mandate.
“We now really do have to act as though it might not rain next year," Marcus said. "Hope is not a strategy.”
Project's future could see wet years
Meanwhile, Painter said he is in talks with the state to massively expand the Airborne Snow Observatory.
Moving beyond the handful of basins the team now monitors, Painter hopes to eventually survey snowpack in the entire Sierra Nevada, providing data that will help the Los Angeles Department of Water and Power and other large water suppliers in Southern California.
The goal is to have three planes in regular operation, not just the one aircraft the team currently rents.
The project, at some point, could be measuring snowpack at sites around the globe, he said.
And though Painter is a snow scientist, the project he's developed has many applications, Gehrke said.
Painter's team used their system to monitor ecological recovery in the area affected by the King Fire, which last fall scorched some 153 square miles in the Sierra foothills east of Sacramento.
The Department of Water Resources' original interest in the project, Gehrke said, was to monitor Sierra Nevada snowpack in very wet years, in part to prevent flooding and efficiently and safely deal with an excess of snowmelt.
It's possible, he said, that the Airborne Snow Observatory could someday in the future monitor a winter with heavy snow in California.
But for now, the team is on drought patrol.
KTLA's Madelaine Hahn and Angel Kim contributed to this article.