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Joy Hall: Dry dirt delivers just desserts in Mohave desert

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Joshua trees in Joshua Tree National Park in the Mojave Desert.


Monday, September 19, 2016

“Next services 90 miles.” The white letters glare on a blue highway sign.

It means the next 90 miles will be pretty quiet.

No cell towers.

No trees.

No signs of life.

No water.

Just dirt, for 90 miles.

This is the Mojave Desert. Astronaut Buzz Aldrin might call it Magnificent Desolation.

It is a far cry from Greenville, where it is raining. Again. Greenville is typically bathed by about 50 inches of rain per year — an eighth inch per day, approaching the climate of a rainforest. Rain is so normal we forget how devastating it can be until a hurricane approaches. Thunderstorms routinely drop an inch of water.

But there are places not so far away where a thunderstorm is catastrophic. In parts of the Mojave Desert there have been years without any rain at all. One inch of downpour in a desert scours the landscape, avalanches the dirt, carves through the roads, flushes the valleys.

Death Valley National Park, in the Mojave in California, typically gets just 2 inches of rain per year, only 1/25 of our rainfall in Greenville. Two thunderstorms make a summer monsoon. The rest of the year is deathly dry.

A 1-inch thunderstorm can really hose a steak. In 1973 the Moses family was in Nevada, near the Mojave, after driving through droves of dust devils on the way to a campground. Now Dad was grilling dinner when a full-blown dust blizzard set in, gusting gales of grit into eyes, nose, teeth — and steak. We lost sight of him staggering toward us with the dust-crusted steak on a fork. Inside the camper, visibility dropped to just inches. Outside, sand blasted man and meat.

Ironically, some of the Nevada desert dust came from beneath an ancient ocean, from a time when the mountain ranges of primitive North America were just tropical island tips and the future desert was undersea, since then heaved up, washed down, and ground to sand. These were bits of grit from the abyss that were burnishing our beefsteak.

Minutes later, it was monsooning. Dad and the steak were washed clean and meal-ready.

Death Valley is deep as well as dry. Its climate comes from seven sets of summits stabbing into the sky to the southwest, including the spiky and soaring Sierra Nevada. Seven times, the mountains interrupt the sweep of Pacific storms into the area. Seven times, the clouds ride up the western slopes of those mountains, cooling and spilling out rain. Seven times, the ex-clouds slide down the east slopes, warming and sopping up moisture in the next valley. By the time they slide down the final Panamint Mountain Peaks, there is only parched air inside. Dried-out basins like Badwater in Death Valley, and Bristol Lake to the south, trap the waterless air within their steep walls, desiccating the landscape.

Death Valley, bottoming at 279 feet below sea level, has more valley, but Bristol Lake has more death. In Death Valley, visitors swarm every prominent pinnacle of the proximate Panamint Mountains. The badness of Badwater is never borne alone. Outside the park, just over the Providence Mountains, is the real bad water. Outside the park is Bristol Lake.

Bristol Lake is the illusory name for a strip of salty sand near the ghost town of Amboy along Route 66 in the Mojave in California. It is midway across the 90 mile expanse to “next services” at the prickly pillars and nettles of Needles, Calif. Most of the Mojave soil supports some spindly sage and saltbush sprouting out of the surface. But at Bristol Lake, the sand stands alone. It is mostly quartz, the silica stuff of spectacles and seasides, that once stood as massive monzogranite mounds but now saltates across the supine sweeps of sand.

Greenville is no Bristol Lake. We have sandy sediment layers, like the desert: meters of mountain minerals off the Piedmont and morphed marine muck from the early mid-Atlantic. But Greenville has rain. Again!

Joy Moses-Hall teaches physics and astronomy at Pitt Community College. She has a PhD in oceanography and is the author of the novel Wretched Refuge.