by More rain is on its way to an already drenched California as forecasters observe two new “atmospheric rivers” forming over the Pacific Ocean on their way to send massive amounts of tropical moisture to the usually dry and sunny state.
After one superstorm dumped over 5 inches (12.7 centimeters) of rain in some coastal regions of California on Wednesday and Thursday (Jan. 4 and 5), which triggered flooding and caused widespread power outages. California has only had a brief respite.
A new atmospheric river is expected to arrive on Friday evening, which will bring more deluge to the coast and heavy snowfall to the mountain areas.
“The cumulative effect of heavy rains following recent heavy rains will lead to several significant flooding impacts this weekend, including rapid water levels and mudslides across northern and central California,” National Weather Service said in a tweet (opens in a new tab) Thursday 5 January. “Flash flooding and debris flows are possible over burn areas [left by wildfires last summer].”
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And that’s not all the current stormy weather has in store for California. The NWS said another atmospheric river is expected to arrive Monday (Jan. 9), bringing more rain and strong winds.
This stormy January comes after above-average rainfall in December, which saw more than 11.6 inches (29 cm) of rain in San Francisco, according to Washington Post (opens in a new tab)which is more than double the average amount for that part of the year.
Most of the moisture that causes the floods is channeled from Hawai’i by so-called atmospheric rivers, channels that form in Earth’s atmosphere and funnel water vapor from humid tropical areas to drier areas further away from the equator.
The type of atmospheric river raging in California is sometimes referred to as the Pineapple Express in a nod to the fruit commonly grown in Hawai’i.
According to NASA (opens in a new tab)atmospheric rivers off the coast of California form regularly during the winter months and typically deliver up to 50% of the region’s annual rain and snow.
However, the current series of atmospheric rivers is particularly treacherous due to their combination with a distinct low pressure area, which led to the formation of an extremely powerful storm, meteorologists call a bomb cyclone, such as the one that hit the area on Wednesday.
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