The atmospheric rivers sweeping through California may be part of the new normal

If we are going to understand these clever Chinese pranksters, we will have to keep up with the language. Courtesy of Washington Post, Wednesday’s lesson is about “atmospheric rivers,” unrelated to the surface of the river, that shine in moonlight through the low haze of summer evenings. It is not about the gift of nature to decorate the group. This is about nature’s gift of all-consuming rage.

In recent weeks, a series of storms has battered California, bringing torrential rains and deadly floods. Storms are typical in winter, including those associated with atmospheric rivers, or tall, broad plumes of water vapor flowing in from the tropics. But as the Earth warms, climate scientists warn that atmospheric river events may swell, causing more destruction.[…]The impact of these storms is paradoxical. Atmospheric rivers generally provide important precipitation for the region’s water cycle. These massive rivers, sometimes carrying 15 times the volume of water of the Mississippi River, provide half of all precipitation in the western United States in less than 15 total days. But heavy rains in a short period of time can have devastating effects on communities. Atmospheric rivers account for nearly 90 percent of California’s flood damage. Infrastructure has been destroyed and more than a dozen people have been killed in storms in the past two weeks.

The climate crisis leads to an increase in atmospheric precipitation, which inevitably falls into one of these atmospheric rivers, which, in essence, overflow their banks, so a flood in the sky turns into a flood on earth.

In a recent study, researchers found that climate change increased the amount of precipitation from two rivers in the atmosphere in February 2017, significantly damaging the Oroville Dam, California’s second largest, and prompting the evacuation of 188,000 people. Atmospheric rivers have produced about 11 and 15 percent of the precipitation due to the warming caused by the burning of fossil fuels. If the same events had occurred in a warmer world — as expected by the end of the 21st century — the researchers found that precipitation amounts would have increased by 20 and 60 percent.[…]According to recent research, the number of atmospheric rivers deemed “mostly or primarily hazardous” to water resource management will increase in intensity, occur in closer succession and result in more precipitation per season. In fact, researchers estimate that atmospheric rivers in the western United States will become 15 percent larger and last six hours longer for every degree Celsius (or 1.8 degrees Fahrenheit) rise.

In addition, warmer atmospheric rivers mean less snow, which means not as much snow melting, and thus less fresh water to drink in certain parts of the country.

“The real danger here is that the entire infrastructure of California has been built with what we understand to be snowpack, which means a natural reservoir throughout the winter,” said Anna Wilson, who studies atmospheric rivers at the Scripps Institution of Oceanography. “We are now in situations where it gets more rain throughout the year. Sometimes it rains on top of the snow.”[…]Precipitation events are expected to increase at elevations, increasing flood risks in particular in the Sierra Nevada, Colorado River headwaters, and the Canadian Rockies.

One thing always leads to another, rolling down the river.

Shot in the Head by Charles B.  Pierce

Charles P. Pierce is the author of four books, most recently America Idiothas been a working journalist since 1976. He lives near Boston and has three children.

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