After two of our five rainiest months ever, we're ready for a break... but grateful for the moisture

I left California three weeks ago, just after Christmas, to spend some time in New England with family. At the time, I was feeling cautiously optimistic about how our winter was shaping up. We'd banked nearly 13" of rain and were at something like 170% of the rain we'd have expected at that point in the winter. The day I left, it started raining and essentially hasn't stopped. With the two-thirds of an inch that we got today, this makes 20 of the last 21 days we've seen measurable precipitation. The end-of-December rain pushed us to 13.28" for the month, making it our second-wettest December in the 25 years since we installed our weather station and a top-5 rainfall month overall.

Then came January. A series of atmospheric river storms paraded across the Pacific and slammed into California. Some were aimed farther north, but still dropped a couple of inches of rain. And one arrived on early in the morning of Monday, January 9th with its plume of moisture directed squarely at the Central Coast. We tallied 5.65" that day, including more than 4" in its peak between 1am and 10am. And when we arrived to see how things looked at the winery that morning, we realized that we couldn't even get there because Las Tablas Creek was flowing over Adelaida Road:

It wasn't until Wednesday that we could make it into our facility, and Thursday that we could reopen our tasting room. Thanks to some great work by our neighbors at Halter Ranch the debris blocking the culvert that was causing the creek to flow over the road was removed before the road was critically damaged. There was a section of Adelaida Road a few miles east of us that wasn't so lucky. And we had to close again this past Saturday because a new storm made access to the winery unsafe. Residents and businesses out here are still picking up the pieces, and what we're seeing is minor compared to the scale of damage around the state, with 19 deaths so far and floods forcing people from their homes from Sacramento to Santa Barbara.

Still, while we wish it had been spread out more, we're grateful to have received the rain. And when I got out in the vineyard today, it was stunning: lush and green from the saturated soils yet with minimal signs of erosion even on our steepest slopes:

After the rain - Counoise and cover crop

There wasn't really any standing water, even at the bottom of the hills, thanks to the remarkable ability our calcareous soils have to transport enormous quantities of water from the surface to deeper layers. That said, there was some water slowly trickling downhill in blocks like this head-trained Mourvedre at the northern edge of the property. It was wet enough that I nearly lost my boots getting this shot:

After the rain - water in head-trained Mourvedre

For all its beauty now, it's clear that things were pretty wild a week ago. You can see the deep cuts in the channels where valleys became rushing creeks (left) and the impact of 36 hours of water flowing over Adelaida Road (right):

After the rain - water flowing from Halter Ranch

After the rain - erosion on Adelaida Road

With nearly half the month still to come, January 2023 is already our third-wettest month in our history, trailing only January 2017 and (from before I started writing this blog) February 1998. We're at 281% of expected rainfall for this point in the winter and above our full-winter long-term average. After three years of drought, that's a huge relief.

Rainfall by month through January 2023

You can see from the rainfall distribution above why this season is so critical for us. We get three-quarters of our annual rainfall between December and March. If we have an extended winter dry stretch, it's almost impossible to make it up later. And drought impacts are cumulative. Grapevines generally do fine the first year of a drought cycle, thanks to their accumulated vigor. But starting the second year, you see the reduction in yields, and by the third year you start to see impacts on vine health and mortality. That's played out for us the last three years. 2020 saw roughly average yields. But 2021 saw yields off by 26% and 2022 saw them decline another 8%. A quick look at our available wines shows many more sold-out than for sale. And that's before we've even gotten to the 2022 vintage, from which there will be several wines we just won't be able to make. So getting rain this winter was particularly important.

Vineyards themselves are typically resilient in the face of extreme rainfall events. Those events typically come in winter, when the vines are dormant, and grapevines' deep roots play an important role in helping hold soil in place. Vineyards that are regeneratively farmed tend to do even better. Both no-till farming and planted cover crops (one or the other is required for regenerative certifications) keep surface erosion to a minimum. The focus on building up the organic matter in your soils helps them hold more moisture. And the biodiversity in regenerative farming systems tends to create a denser web of life than monocultures. Witness this section in the middle of the vineyard, which a decade ago was one of our most erosion-prone areas but which we planted to a mix of perennial crops that would act as attractors for beneficial insects. The combination of shrubs and deep grass, already well-established because it hasn't been tilled in years, made for one of the least-soggy sections of the vineyard:

After the rain - Biodynamic plantings

Looking forward, we're supposed to get a few more showery days and then a solid week at least of sun. That will be welcome for everyone, from vineyard to residents to businesses. It should give the county a chance to get out and repair the damaged roads. It should shift the cover crop into overdrive, and make for some very happy sheep. It will give the soils a chance to transfer the water to deeper layers and free up space at the surface for the next storm. It might even give us a chance to get started on our pruning, which we've been unable to do because pruning in wet weather encourages the spread of fungal diseases. But as happy as we are with what we've received, we're hoping this isn't the end of the rain. The local reservoirs still have significant room; while Lake Nacimiento is at 87% capacity, Lake San Antonio is only at 32%. At Tablas Creek we're chipping away at an accumulated rainfall deficit of 28" from the last three years of drought. Plus there would be benefits during the growing season, as soils with high moisture content stay cool longer in the spring and delay budbreak, which would reduce our risk of frost damage. And on a purely aesthetic level, there's a particular character to the green here after winter rain that I love. Who wouldn't want more of this?

After the rain - New Hill and Jewel Ridge

If you were negatively impacted by these storms, please know you have our deepest sympathy. It's been a rough couple of weeks for California. But if you were worried that the vineyards here would be suffering, hopefully we can at least put that to rest. We have high hopes for the 2023 vintage.  


What does the latest atmospheric river storm mean for Paso Robles Wine Country's rain year?

[Editor's note 1/10: I've posted a quick summary of the flooding and other impacts of our January 9th atmospheric river storm in a comment. We're posting regular updates on our Twitter, Facebook, and Instagram pages. And I'm planning a blog with a more comprehensive report next week.]

Our current atmospheric river storm, which isn't even over yet, has received a lot of press with even big east coast papers like the New York Times and Washington Post giving it front-page coverage. The San Francisco Chronicle is dedicating most of its homepage to stories about the storm and its impacts. Down here in Paso Robles we got 3.53" of rain yesterday and last night, and have received another quarter-inch of rain in showers this afternoon. With other storms just a day or two out, I thought I'd do a quick assessment of what the impacts of the rain have been so far and what we're expecting next.

The tl;dr for those of you who start meals by eating dessert: the impacts to this point have been essentially all positive for us. We've already surpassed our rainfall for the winters of 2019-20, 2020-21, and 2021-22. The ground is saturated, but we haven't seen either flooding or noteworthy erosion. And Las Tablas Creek is flowing for the first time since early 2019:

We're at just about 200% of our expected January 5th total for the rainfall year which started in July. Looking month by month, we more than tripled our normal December rain and finished just a fraction of an inch behind 2004 for our wettest December ever. And unlike last year, when we had a wet December and then an almost totally dry spring, it looks like we'll surpass our normal January rainfall this weekend. Here's what it looks like so far (January's total is through this afternoon, while the expected total is for the entire month):

Rainfall by Month as of January 2023

For the rainfall year, we're up to 19.6" of total rain, with more than half the rainfall season to go. That's terrific. The fact that Las Tablas Creek is flowing is a great sign of the saturation of the soils; there are several irrigation ponds upstream from us, and other than some surface runoff that happens during storms, it's not until those ponds fill up and the top several feet of soil is saturated that the creek flows continuously. Today, the creek is flowing merrily into our lake:

Las Tablas Creek and lake

In the vineyard, you can practically hear the cover crops growing. Although we move the sheep out of the vineyard during rain events (both to provide them shelter and to keep the soil compaction that they cause in very wet weather to a minimum) there will be ample grass whenever it dries out enough to let them back in:

Cover Crop

You can get a sense of how excited they are by all this grass from the video we shared Tuesday on Twitter:

Most people who haven't spent a winter in the Paso Robles area think of it as a desert climate. And it is, in the summer. But the six winter months are wet enough on average, at least in the western fringes of the AVA where we're located, to qualify as a temperate rain forest if those months were extrapolated year-round. That fact, combined with the hilly topography, means that we're pretty well set up for heavy rainfall events. You can get some localized stream flooding (though Las Tablas Creek hasn't flooded in the two decades that I've been out here). You can get some minor mudslides where the roads have been cut through the hills. And you can have downed trees from wind and wet soils that can knock out power. But our calcareous soils are exceptionally porous, which means that they transport massive volumes of water from the surface to deeper layers before they reach saturation. By the time they do saturate, the winter grasses tend to be well-enough established that erosion is minimal (as evidence, check out my photo essay from January 2017 after we'd broken our record for our wettest month ever). Finally, the hilly landscape means that the extra water by and large flows off and fills up our reservoirs rather than flooding our towns. Lake Nacimiento, into which Las Tablas Creek and the rest of our watershed empties, was up to 747.7 feet as of today, 32 feet higher than it was just over a month ago on December 1st, but despite the billions (yes, with a "b") of additional stored gallons of water, the reservoir is still at just 38% of its capacity. Lake San Antonio is at just 13% of its capacity. We can get a lot more rain before we have to start worrying about where it might go.

Looking forward, we're expecting another major Pacific storm Sunday into Monday. And it seems like there's another one lined up behind that later next week. But while we'll be watching the forecast we're not expecting the potentially dangerous impacts for which northern California is preparing. Some of that is because it seems like these storms will be aimed such that the largest precipitation totals will be a little north of us. But just as much, it's because our soils and topography are uniquely well suited to dealing with large amounts of water in a short time. After all, we got more than a dozen inches of rain in a single storm in January 2021, and the impacts were almost all positive.

So while I'll be checking our weather station's totals regularly it won't be with dread. The opposite, really. After consecutive drought-reduced crops (see my recaps for 2021 and 2022 if you want the gory details) I'm hoping for a historically wet winter: something that will replenish our aquifers and reservoirs, delay budbreak to a more normal time frame, and set us up for a couple of years. This has happened before, in winters like 2004-05, 2009-10, and 2016-17. And it feels like we're well on our way to a similar result this year. Let's keep it coming.

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