Heavy storms this winter have produced one of the heaviest snowfalls on record in California’s Sierra Nevada, along with an unusual amount of snow in the low mountains.
However, this much snowfall at lower altitudes will become increasingly rare in the coming years as climate change drives temperatures higher, according to a new study.
In a study published this week, scientists have found that mountain snowlines in California have grown higher and could rise significantly higher if nothing is done to slow the rate of snowfall. global warming. The researchers predict that between the years 2050 and 2100, rising temperatures could push snowlines on average 1,300 feet to 1,600 feet higher across the Sierra Nevada and southern Cascades than a century ago.
As more precipitation falls due to rain rather than snow at lower elevations, changing flow patterns will pose significant challenges to water management in California and to the operation of dams designed designed to capture and store melted snow.
“The snow lines are increasing,” said Alexander Gershunov, a research meteorologist who co-authored the study with other scientists at UC San Diego’s Scripps Institution of Oceanography.
“If we look to the end of the century, snow will be limited to much higher altitudes for most of the year,” says Gershunov. “Low-altitude mountains will be more and more likely to be snow-free.”
After examining more than 70 years of snow data, the researchers concluded that with unmitigated global warming, the mountains of California could lose more than half of their seasonal snow cover.
They said average November-March snowfall in the northern Sierra could fall by more than 70 per cent by the second half of the century, while a drop of around 40 per cent could occur in the higher mountains in the center. Sierra and southern Sierra.
Likewise, the study also shows that a large increase in the amount of precipitation that falls when it rains will result in heavier runoff during the winter.
That means larger flows are flowing from the mountains rather than melting gradually, a trend that is already evident and will complicate the work of dam managers, Gershunov said.
“It becomes more difficult to balance the need for flood control that reservoirs provide with the capacity to hold water,” says Gershunov. “We have to learn how to make water out of flood water.”
For one thing, he said, the trends show why it’s important for California to ramp up efforts to capture and use floodwater to groundwater replenishment — which state water officials have said is a priority to adapt to the more intense swings between drought and wet weather conditions.
Even if the average snow lines recede, California will sometimes still have years of heavy snowfall, the study’s authors say.
Scientists found that as the planet warms with increased greenhouse gases, more mountain snow flows into atmospheric rivers, which are warmer and often have higher snow lines than winter storms other. And according to other research, such storms will grow stronger As the temperature increases, more steam is transported.
“At very high altitudes, ironically, we are more likely to accumulate unprecedented snow, because atmospheric river storms in particular are becoming wetter,” says Gershunov.
The scientists also looked at how snowline retreat could affect the ski industry after 2050 under a full-blown warming scenario. They estimate that lower-altitude ski areas, such as the Northstar California Resort, in Truckee, and Palisades-Tahoe, in the Olympic Valley, could lose more than 60 percent of average snow accumulation.
Higher slopes, such as those at Mammoth Mountain, in Mammoth Lake, are predicted to have smaller average snow losses.
The studywas published in the journal Climate Dynamics, sponsored by the United States Bureau of Reclamation and the California Department of Water Resources.
The study provides new insights into the transition to more rain and less snow, including watershed predictions that could help show where gaps in water management may lie, Michael Anderson, a climatologist with the Department of Water Resources said. This and other research, he said, “helps guide some of the choices we’re making in establishing climate change adaptation strategies.”
The findings add to other research showing that average snow cover has decreased in most areas of the continental United States, and that big fall in the snow could happen by the end of this century.
The latest research focuses on snow lines, said Philip Mote, a climate scientist and graduate dean at Oregon State University who was not involved in the study.
“It should come as no surprise, though, that this year’s overall warming will result in less snow. The questions are how much and how to deal with it,” Mote said.
He say thick layer of snow of 2023 is “within the normal range, but heavy snow years will continue to be rarer.”
“I hope that in 20 years, we will still be reminiscing about 2023,” Mote said.
Mote points out that the study used a high-emissions scenario of global warming, but it doesn’t appear that emissions will reach that trajectory, so he hopes “things won’t be as bad as they are.” This article describes.”
Gershunov said the authors did not take into account efforts to mitigate climate change.
“There is still room to mitigate some of the impacts that we have identified,” he said. “I would like to see both more active climate mitigation globally and better informed local and regional climate adaptation, which this kind of research will inform.”