Looking for an ark
OK, think fast, I’m gonna throw some numbers at you.
Two weeks ago on Dec. 27, our season rain total stood at 16.95 inches which was 9 inches below the historical average for that date.
A fortnight later, on Tuesday, Jan. 11 as I write this column, our season-to-date total is 39.20 inches, which is 7.10 inches above the historical norm 32.10 inches. Our annual historical rainfall is nearly 67 inches. What happened?
Well, it’s rained 16 out of the last 17 days, registering 22.25 inches of precipitation.
To put this in perspective, 2 years ago during the worst drought in California’s history, Laytonville received only 29 inches of rain. Amazingly, even with that record low, our Long Valley aquifer recharged itself. And already here we are in early January, and we’ve already surpassed that measly 29 inches by 7 inches. From November through March, historically each month averages 10plus inches of rain. Our rain year runs from July 1 to June 30.
I’d say we’re in pretty good shape compared to recent times.
By the way, I just read a CapRadio report that pointed out it’s been years since California has seen a series of storms like those hitting the state now. They’ve caused evacuations, power outages and flooding, all of which are a hazard to people in impacted areas.
“In terms of overall flood risk, one atmospheric river is typically not enough in order to drive severe concerns,” said Paul Ullrich, a professor of Regional and Global Climate Modeling at UC Davis.
But multiple storms in a row is a different story, he said.
“When you have these sequential atmospheric river events, then you really have to be worried about reservoirs overtopping, soil saturation and other drivers of widespread flood damage,” Ullrich said.
This dump of precipitation might also have positive impacts on California’s water supply. Ullrich said he remembers a series of atmospheric river events that hit California in 2016 and 2017 and helped “pull us out of that major drought that we had at the time.”
“Probably, we’re going to see that again this year,” he said.
But although this rash of storms could help the state’s water supply ahead of the summer, researchers say it also reveals weaknesses in the state’s flood-prevention infrastructure and points to more severe weather to come.
During the fall of 2022, the National Oceanic and Atmospheric Association (NOAA) predicted California would have a relatively dry winter — a prediction that now, of course, has proven incorrect.
However, in my annual Fall forecast I predicted that this winter we would most likely experience something closer to historical weather and rainfall patterns.
Why was my forecast more accurate than NOAA’s?
Purely a combination of luck and my reliance on decades of local weather records. Local weather data is, I believe, critical to understanding what may be in store for us from Madre Nature.
Mendocino County has over 300 micro climates, all with distinguishing weather patterns.
For example, as the crow flies it is 8 miles from Laytonville to Branscomb in southwest direction and 13 miles over the road. Yet, on average Branscomb’s precipitation exceeds Laytonville’s by approximately 20 inches, annually.
We have micro climates separated by less than a mile in Mendocino County, each with its own unique meteorological conditions.
Ullrich said California’s winters are notoriously hard to predict because of the state’s extreme and variable weather.
However, Ullrich added that the difference between a “dry” and “wet” winter can be very slight in California.
“California is very unique in that so much of its precipitation for the year comes on so few days,” he said. “As a consequence, if you take some of those days away, if you turn them from wet days to dry days, suddenly it changes the whole total annual precipitation received by the state.”
Ullrich said the level of precipitation coming from this storm isn’t unprecedented, for the most part. Overall levels of annual precipitation in Northern California have stayed fairly consistent.
But a warming climate has encouraged more extreme weather events, he said. Warmer temperatures mean the capacity for more water vapor held in the air, which can lead to more precipitation all at once.
“What we are generally seeing is that some of the more extreme events are becoming more common,” he said. “What used to be a 1-in-100 year event is now becoming a 1-in-20 year event, or even more frequent than that.”
An alternative view on what’s happening is one way or another Madre Nature always gets her way.
Jim Shields is the Mendocino County Observer’s editor and publisher, observer@pacific. net, the long-time district manager of the Laytonville County Water District, and is also chairman of the Laytonville Area Municipal Advisory Council. Listen to his radio program “This and That” every Saturday at noon on KPFN 105.1 FM, also streamed live: http://www.kpfn.org