Dragon Tongues: The Origin of Atmospheric Rivers from David McCloskey, designer of the Cascadia bioregion map. Learn more about David’s work at the Cascadia Institute.

Flickering tongues of fire leap up from the steamy orbits of the Northern Equatorial Current and transform into Atmospheric Rivers pounding our coasts. They say these plumes of sub-tropical heat and water laden clouds can carry 7-15 times the total flow of the Mississippi River. Because of the “Pineapple Express” label, I had assumed these warm, wet, fast-moving bullet trains originated around Hawaii, but that’s not the case—instead, they pass through the sub-tropics, but actually originate as roiling plumes spun off the equatorial region. So one of the largest inputs to Cascadian waters comes from the great circum-equatorial current. This is not really surprising, since this area is the great heat engine for the planet.

 

The equatorial regime is truly extraordinary in having three major currents packed close together as if striped on a spinning ball—there are two mirroring currents on either side of the equator running westward—the Northern and Southern Equatorial Currents—separated by a relatively narrow Equatorial Counter Current running eastward. Here’s where the Intertropical Convergence Zone (the “ITCZ”) is the home of the most intense moisture and heat, strong convection, daily thunderstorms, and lush rain forests. Somehow it makes bioregional sense that the most intense heat zone on earth is found at the zero-point latitude (just as the coldest zone is found at 90 degrees), because it’s the places of Earth which generate and articulate weather patterns (whereas the sun is only a general “input.”) Taken all together, this region is truly a river of fire encircling the globe. It’s a kind of an origin belt for all weather on earth.

 

Atmospheric Rivers now make more sense to me because they’re born in a great circum-equatorial ring of fire at the globes’ widest girth wrapped around zero-point latitude. The sun is, of course, the ultimate source of all these sky energies. Sometimes the mid-day insolation is so intense from the sub-tropics into the equatorial zone that you can literally feel the photons hit your skin, and soon you have to seek shelter or shade to escape such an intense radiant bath, or else expire. Try to do too much for too long, and you feel irradiated, solarized like the burnt-out soils….

 

The Northern Equatorial Current is a great central belt encompassing the globe. It gathers the first formation of the bursts of energy streaming outward from the tropical zone. The westerlies are oddly reversed in the next layer north by sub-tropical winds. The dragons’ tongues arise as episodic outbursts flaming forth that then roll back westwards from the easterlies to form plumes of water vapor streaming northwest. What apparently happens is that surface winds and shear between the reversed belts pile up mounds of water. Eventually, these churning bodies of inter-mixed hot water and vapor become top-heavy, and the mounds fall over or get pulled away, snagged by winds heading northwest. As the agitated water surges back and forth, it rises and bends backwards toward the west coast of North America.

 

With their enormous load of warm water vapor, the flame then stretches out, like pulled taffy, into long plumes of moisture-laden “rivers from the sky.” The volumes of water and distances involved are truly impressive— the “Pineapple Express” segment from Seattle to Hawaii is about 4,300 km long, with perhaps another 2000 km to its equatorial origins, for a total of at least 6000 km, while the water load carried is estimated to range into the trillions of gallons! Perhaps the combination of two major water sources—the Aleutian Low and the sub-tropical (tropical in origin) Atmospheric Rivers—converge to help create Cascadia as having the greatest Freshwater Discharge (FWD) of any region in North America—2.7 times the total Mississippi Basin….

 

One marked difference in shape is that the Atmospheric Rivers follow mostly a straight-line path, whereas the Aleutian Low comes in a gyre spinning counterclockwise, forming an ever-more tightly bound core in which one of its flailing outer arms hits the coast at an oblique angle. When it does hit the north/south running mountain ranges at a right angle the rain truly pours! The core of the Atmospheric Rivers’ plume is the center track of the oncoming river, running faster than the sides and carrying heavier loads of water vapor—this more intense section hits like a hammer…

Source: NOAA Atmospheric Rivers Portal

The Atmospheric Rivers’ steam up to the northwest like bullet trains, keep roiling and surging until they hit the western wall of the North Pacific coast; sometimes they make a final surge in a last push up-and-over the high ragged walls of the coastal mountains like the B.C. Coast Range, even to the extent of washing over into mountains, valleys, and sounds, like a crashing wave. In order to make the final push up and over, they’re forced to “climb the wall” of the steep mountain ramparts, causing the clouds to rise, condense and cool with increased elevation, generating tremendous rain fall, which is called “orographic precipitation” (yet another way the place makes weather). Sometimes these rivers above are so powerful they punch through the myriad mountain barriers from the Coast Ranges through the Cascades to some of the interior ranges like the Columbia Mountains over the Continental Divide along the high Rockies and beyond, out onto the High Plains into the mountain masses of Colorado, and even the mid-section, or heartland of the country.

 

To us “here down below” this is part of “The Pacific Wave,” crashing against the exposed outer coast, “climbing the wall” and spreading precipitation into the interior. At the same time, the drenched “rain shed” is mirrored by its corresponding mirror of a dried-out arid “rain shadow,” thus establishing a common pattern of “topoclimates” that repeat with each successive mountain range (yet another way place makes its own climate). And, of course, the return flow is marked by all the ten thousand rivers streaming back to the sea. In short, the on-coming rain is the first phase, while the rivers are the return flow—two sides of the Pacific Wave.

 

Dragons and their tongues primarily served as water deities in East Asian mythology, responsible for waters and winds and weathers. We now come in our new state of benighted knowledge and environmental ravaging to meet the need for a grounded bioregional mythology to portray powers controlling our world such as Atmospheric Rivers, Floods, Earthquakes, etc. Perhaps its time to see Atmospheric Rivers for what they are: dragon’s tongues flickering out from the hearth of the central ring of fire, and in so doing, signaling what time it is.

 

From a static point of view, little sense of these crucial dynamisms interacting comes through. However, the perspective radically shifts when presented an animation of real phenomena which compresses time and space—all of this and more is revealed, for instance, through the great NOAA videos of “Integrated Water Transport” speeded up for most of the planet over a month or year. When the latent, invisible framework comes through, we can then see the whole unfolding through its parts. In these and other ways, we need to learn to “think like a Planet.”

 

What is the twinned future of Atmospheric Rivers and a bioregion like Cascadia? Atmospheric Rivers already seem to be growing in frequency and intensity. Why so many of them, so fast? They keep coming, one after another, so many I’ve already lost track. Why are they aimed where they are? Why do they seem to hit the same place? And what does the future hold? In a world of warming global temperatures, the seas grow warmer and can hold more water vapor. What is certain is the more heat concentrated in tropical oceans and air masses, the greater the need to dissipate heat from higher to lower concentrations, and that means more, probably many more, Dragon Tongues flickering outward north from the central ring of fire to our shores, perched on the verge of mountains and the sea stretched all along the western wall. Dragon Tongues rise as flames of fire bursting off from the central ring of fire, then streaming far, far away, as rivers from the sky taking a straight line to water our shores.

 

David McCloskey,
Dec. solstice time, 2025,
Cascadia Institute