Atmospheric Rivers, the Pineapple Express, and a Large Wetland

California’s drought is, if not broken, seriously dented, especially for the upcoming summer. As of Tuesday the 17th, average depth of snow in the Sierra Nevada Mountains was one and two-thirds the thirty-year average and increasing. As usual, once the media could get in, and the storms proved to be numerous and productive (and photogenic. Large bounders on the highway are cool. So are floating cars if they are somewhere far away from you,) people began trying to blame someone for the “atmospheric river.” (Climate change! Global warming! Cars and trucks! Hollywood’s moral turpitude!*) Um, well, not really. This isn’t new, just mildly uncommon.

California and parts of the western coast of North America have a Mediterranian Climate. This means that summers are warm and dry, because the ocean currents tend to be cold, and discourage evaporation. Also, winds from inland bring warm, dry air down from the mountains and push out to sea, sending any storms away from the coast. This makes for predictable seasonal weather – you can plan a picnic for July 15 and be 99% sure it will be sunny and warm, even if you set the date in December of the previous year. Likewise, November through March tend to be moist and cooler, although how wet and how cool vary from year to year. A strong La Niña pattern will send the moisture well to the north, and Seattle will get lots of snow, as will British Columbia. Southern California will be dry, and soon start worrying about water limits and rationing and Mega Drought. An El Niño year means California wades, the northern Rockies are relatively dry, and Arizona has a ski season as well as flooding. Remember when the Colorado River almost ripped out Glen Canyon Dam in the early 1980s? El Niño years. We’ve been having a series of La Niñas.

The short-term pattern his shifted, thanks to a series of Pacific storms that formed well south of the usual track in the Gulf of Alaska. These are sometimes called “the Pineapple Express,” because a southern branch of the jet stream picks them up from as far as Hawaii, and slings them over the west coast. From there they might go straight east, or north, or more rarely a little south**. They dump rain and snow on the West Coast.

Since California lives and dries by the winter rainfall and snow pack, all this would be great if it were spread out between October 1 and March 1. However, it is all in December-January, and the overload has filled rivers, flood plains, reservoirs, overloaded snow-removal equipment, and generally made a mess of the place. This is also not new. If you build a lot of hard surfaces along a river, it will rise higher and faster than before, causing flooding. Land-slides are part of the process as well, which people have observed going back to the Spanish colonial period. That’s just what the geology does in that part of the world, especially when very wet.

We’re nowhere near the mess of 1861-62 yet. Back then the Central Valley was still a wetland for the most part, undrained and grass covered, with meandering streams and only one major outlet. So when lots and lots and lots of snow and rain fell, and fell, and fell between November and January, some of it very hard and all at once, the Central Valley went under water. Literally. Sacramento was navigable by boat. Arizona, Washington, Oregon, and New Mexico also had flooding, and the Texas Panhandle finally saw the terrible drought of the 1850s broken for a while. A drought had plagued the area in the 1850s, and the shift to a very strong El Niño broke the drought hard. Very hard. Now, since there were far fewer people to be afflicted, it was a pain but not the disaster it is today. Only a few thousand people died (!) The rest of the country was more worried about the Civil War (and in TX, about the Comanches raiding again). It wasn’t that flooding hadn’t happened before, but that the scale was so impressive. Thirty-feet deep floodwaters are uncommon, and memorable. The good news was, it refilled the aquifers. The bad news was, it wiped out the ranches in the Central Valley along with a lot of other property, and cost human lives, and made a mess of the place. Wired has a pretty good article, if you skim the climate-apocalypse bits. The cautions and observations about the long-term sequence of floods and modern consequences is food for thought – and disaster novels.

Today, parts of the Central Valley have sunk from ground-water pumping. California’s water storage and use policies are . . . I will be charitable. Convoluted, awkward, complex, and perhaps slightly off in their use priorities. The current series of storms will be good in the medium-run, especially this spring and summer as the snow-pack melts and provides summer in-stream flow. Right now, it’s rough on people, livestock, and wildlife. It will also be a major concern for produce growers and other things, since so many fields are under water – literally – and will be water logged for a while. What the state of the soil will be after the water drains is to be seen. We may lose some to sand and other sediment deposits.

What we’re seeing isn’t new, just news. It’s not caused by people but by atmospheric pressure and temperature systems. Rain happens, and sometimes a lot of rain happens all at once.

*The Book of Genesis says no more global floods. There’s nothing about a localized scouring not being an option.

**The southern track is more common with El Niño patterns, and that’s where southern NM, TX, and northern Mexico get winter precipitation. Or we get it from the Gulf of Mexico, but that’s rare this time of year.

12 thoughts on “Atmospheric Rivers, the Pineapple Express, and a Large Wetland

  1. The Book of Genesis says no more global floods. There’s nothing about a localized scouring not being an option.

    Does that mean that we can hope that the California Lefties will be washed into the Pacific? [Crazy Grin]

    • Lefties make up 10% of the population. Even though they have problems with standard scissors and learning to write from left to right, they don’t deserve to get washed into the Pacific.

      • Indeed. But I still sometimes think fondly of a certain actors, producers, academics, and public intellectuals perched on living room tables, watching in dismay as their $100,000 throw rugs wash out the front door. No, I’m not a kind person some days.

        • Well, if it’s just property . . . I think it would be as funny as a three-dollar bill.

  2. Victor Davis Hanson has mentioned that the big users of ground water in the Central valley are the almond growers. They’ve pumped enough water that many of the smaller farms no longer have viable wells without expensive redrilling.

    We had some occurances of that in S. Central Oregon with the extraordinary drought cycles, and at least one town had to redo its well. The last I looked, the state prohibited new agricultural wells in the area. (Looks at river and our relatively high water table and breathes a quiet sigh of relief. So far.)

  3. Is there any feasible tech or infrastructure to direct more of this water down into aquifers? Or am I enjoying a frequent pipe dream?

  4. You want time for the water to seep and percolate down, so it loses contaminants on the way. Hopefully it doesn’t pick too much new stuff. A nice layer of limestone is good for this. California will need a number of years like this to begin recharging. May be time for ranching and cattle again.

      • You would have to get a lot of permits, and hope that the renewed E.P.A. wetland rules don’t require you to keep water there. There have been attempts to do something similar in Texas with the Ogallala Aquifer through the natural playa lakes, but the danger of getting contamination into the aquifer if the water is piped into the gravel/sand beds too quickly (and the lack of good results) ended the experiment.

  5. Ah yes, the Pineapple Express… Made for a quick trip to the coast, 4.5 hours, but you didn’t want to fight 200kt headwinds going back, or the clouds/rain. We would fly down to North Island, gas, and fly the ‘southern’ route back to Hawaii, about 300 miles further and still be under the 12 hours it would take from SFO. The sad part is the amount of runoff California is letting get away due to their lack of planning, catchments, and reservoirs… Thanks to the econazis.

  6. It’s been quite eye-opening to see (yet again) what a difference 50 miles or so makes in California’s weather. On the coast there were disasters, likewise in the Sierra foothills. In the Central Valley we got less rain (2 inches rather than 5, in one instance) and milder winds (25 mph rather than 60+). Our electricity was interrupted 2 or 3 times, but only one of those was for more than a few minutes.

  7. Those were the days, my friend, we thought they’d never end…. I was in Utah in 1983. A succession of unusually wet years led to things such the spring snowmelt turning Salt Lake City streets into rivers (with the aid of lot of sandbags…) Enough went into the Great Salt Lake and Utah Lake that a few people thought Lake Bonneville was coming back. A mudslide dammed the Spanish Fork River and created a lake. (wiping out the tiny town of Thistle.) There were those who said, Yay! Free reservoir! But it wasn’t in the regional land use plan and not properly engineered for safety, so it was promptly drained. On the other side of the mountains, it all went down the Colorado. Lake Powell and Lake Mead are both mighty thirsty about now and will be thankful for this year’s snowpack, although I don’t know if we can keep Los Angeles from draining them faster than the water comes in.

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