Atmospheric river slams California with record rain
Floods hit California as an atmospheric river conveyor belt of tropical air moves through, with another similar event expected in the coming week.
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San Francisco has second rainiest day on record
Heavy rainfall hit California, bringing flooding to San Francisco and neighboring areas and leading to inundated roads, landslides, and evacuation orders. New Year's Eve saw the second-highest daily rainfall total on record in downtown San Francisco (with records going back to 1949), with 5.46 inches recorded. This is more than 25 percent of the annual average rainfall and only 0.08 inch short of the all-time record set in November 1994.
The recent downpour has been part of an atmospheric river event – where a conveyor belt of warm, moist tropical air interacts with and feeds into mid-latitude storm systems, strongly enhancing rainfall potential.
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Due to an atypically dry start of the 2022 year, San Francisco witnessed about 20 percent of normal rainfall totals through early October. Prior to this event, rainfall totals since October were close to average; despite December's wet end, San Francisco ended 2022 with only almost two-thirds of the annual average rainfall.
After a short lull in the heavy rainfall at the beginning of this week, another atmospheric river is expected to hit California from Wednesday onwards, with more heavy rain, strong winds, and mountain snow. About 3 inches of rain is expected with the coming storm system for lowland areas around San Francisco Bay, with totals exceeding 6 inches in the coastal mountains to the north and south.
