Coastal California is currently grappling with heavy rains from atmospheric rivers, particularly rivers in the sky that collect moisture from the tropics and redistribute water to higher latitudes. Forecasts show that the current El Niño pattern is also leading to lots of heavy rain and generally unstable, wet weather.
Incessant humidity is causing life-threatening flooding in some of Southern California’s most populous cities, including Los Angeles and San Diego; these cities were already drenched from the previous heavy rain late last week.
Climate change and a strong El Niño event may play a role in the intensity of impacts created by atmospheric rivers when they hit the West Coast, scientists say.
Although it is not possible to say that a particular weather event is caused by climate change as it occurs, research shows that climate change is making the effects of naturally occurring events, such as atmospheric rivers, more intense.
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There are many variables involved when linking river events in the atmosphere to climate change, and another important variable this year is El Niño. Some experts warn that more research is needed to make the link between climate change and atmospheric rivers more specific and definitive.
Julie Kalansky, a climate scientist and deputy director of operations at the Center for Western Air and Water Extremes at the Scripps Institution of Oceanography at the University of California, San Diego, told ABC News there is still much to learn about potential connections between them. Broader connections can be made to atmospheric rivers, climate change, and extreme impacts brought by events such as El Niño.
“Moreover [California’s] According to model projections, precipitation, that is, rain and snowfall, will come from atmospheric rivers,” Kalansky said.
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According to the Fifth National Climate Assessment published in November, in a warming climate, winter precipitation will fall as rain instead of snow, and since winter is the season in which the overall warming is greatest, there will be greater increases in extreme precipitation events during the winter season. .
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Experts say that this change in precipitation type may be accompanied by more frequent and intense extreme precipitation events, adding that atmospheric rivers have the potential to cause more extreme precipitation events in the future.
As global temperatures continue to warm, they allow the atmosphere to hold more moisture, causing precipitation events to become more frequent and extreme, according to the latest research from the National Oceanic and Atmospheric Administration.
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More intense extreme rain events also increase the frequency and scale of flash floods as water flows become greater than existing infrastructure is built to handle.
In the continental United States, California already experiences the most variability in wet and dry conditions from year to year, Kalansky told ABC News. Southern California has a much more variable climate than Northern California, even without the current El Niño event, which largely contributes to the extreme humidity in recent weeks.
“Climate projections show that variability between wet and dry will become even more variable in the future,” Kalansky said.
In states like California, recent research shows that human-caused climate change may result in less frequent but more intense precipitation events. According to the California Climate Adaptation Strategy, severe fluctuations, for example, from a devastating drought to record-breaking rainfall, will become more common and extreme in the coming decades, which could lead to more devastating impacts.
According to NOAA, the current El Niño pattern favors lots of heavy rain and an overall period of unstable, rainy weather. During the winter months, El Niño causes above-average precipitation conditions across much of the southern United States, including a large swath of California.
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