Thanks to atmospheric rivers and cyclone remnants pummeling the NorCal coast since October 1, this is officially the wettest water year to date since 1983 — and this is great news for the drought.
Yes, it was a gloomy and soggy Christmas week. And this week is only looking slightly better. But everyone knows how badly we needed this rain, and it's only a deluge of storms like we've been having that are going to get us out of what was looking like a never-ending drought.
And now the National Weather Service noted on Sunday evening that as of 5 p.m., SF had officially eclipsed a recent record rain year to date. With each of our "water years" going from October 1 to September 30, this rain year to date has seen over 15 inches in the city, which is the most rain that fallen between October 1 and December 26 since 1983. And more records may fall before the year is out!
At 5 pm San Francisco 15.04" rain since Oct 1, 2021 is 8th wettest water year to date (ytd), wettest since 1983 w/15.70" rain for same period; 1983-1984 La Niña.— NWS Bay Area (@NWSBayArea) December 27, 2021
SF top 5 wettest water ytd (ending Dec 26):
1. 23.77" 1889
2. 17.68" 1849
3. 17.44" 1885
4. 16.74" 1866
5. 16.48" 1852
Still, we are not likely to break the all-time record for that almost three-month span which was set in 1889 — when a drenching 23.77 inches fell between those dates.
To put this in further perspective, the winter of 1861-62 was a record rain year for California, and caused what's considered a 100-year (or 200-year) flood in January after over 24 inches of rain fell in one month (Jan. 1862). That was capped off by a warm storm that melted a huge amount of accumulated snow in the Sierra. (The resulting flooding is considered the worst disaster in state history — and something similar is likely to recur, though hopefully levees around Sacramento and other infrastructure built since that time will lessen the damage.)
Even in that very rainy season, San Francisco didn't see as much rain between October 1 and the end of December as we've seen this year. That year, 1861, SF saw zero rain in the month of October, followed by a stormy couple of months that totaled 13.64 inches between November and December.
This is now that the eighth-wettest water year-to-date after 1983 — and it should be noted that the winter of '83-'84 was also a La Nina year. If the city sees another inch and a half between now and when the rain dies down on Thursday, we could be looking at the top 5 of recorded water years-to-date — with number 5 currently being 1852, when the city saw 16.48 inches of rain (up to Dec. 26 that is).
But here's a radar model from the weather service about the next bout of rain to come, and it looks to be a bit lighter. So we'll see.
A much colder air mass will arrive tonight into Tuesday result in snow levels dropping to around 1,500ft. Thus, could see rain/snow mix in the North & East Bay Valleys early Tuesday morning with accumulating snow in the region's higher elevations. #CAwx #CAsnow #BayAreaWX pic.twitter.com/ijAE5e2UDK— NWS Bay Area (@NWSBayArea) December 27, 2021
Photo: J. Adam Moore/Twitter