John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
El Niño could roar back to life in March, potentially dropping more than 100 inches of snow on the mountains.
Last week, the National Weather Service shared this graphic showing just how little rain San Francisco has gotten since October, compared with other El Niño years (look for the dark-blue line):
In the past, powerful El Niños have typically delivered about 22 inches of rain to the city by this time; the current amount is far below that. To reach the El Niño average of 30 inches by the beginning of summer, the NWS writes, “we would need more than two tenths of an inch every day through the end of May.”
That seemed improbable a few days ago—and still iffy today—but there’s a developing weather pattern that’s boding drenching days ahead for drought-struck California. Weather models are predicting torrential rains through the weekend, with more than 12 inches of precipitation possible in the mountains. (Under the right conditions, that amount of rain could equal more than 10 feet of snow.)
Models can be spectacularly wrong, but it does appear something powerful is brewing. The San Francisco NWS warns of the risk of “urban flooding” over the weekend, with strong winds that “could topple trees and bring down power lines” and cause blackouts. The agency adds that models are predicting the arrival late next week of an atmospheric river—a band of atmospheric moisture that can contain the water-flow equivalent of the Amazon River—raising the “potential for additional widespread rainfall.”
The incoming storms have meteorologists abuzz; here’s some of what they’re saying:
Got snowpack? The Sierra will have plenty by mid-March per GFS. Highest peaks could receive 100+ inches! pic.twitter.com/eBZOVLqtYu— Brian Lada (@wxlada) March 1, 2016