It’s a gorgeous day in the California desert. An autumn breeze, cool for the desert at 80°F, makes the dry leaves of big galleta grass rustle. Two hundred yards or so off to the south, the raucous song of a cactus wren echoes off the rocks. It seems loud, despite the distance: it’s just that everything else is so quiet that hearing a bird from a tenth of a mile away is pretty easy.
Eyes closed, you listen for more: the hum of a passing dragonfly; the chatter of a pair of antelope ground squirrels; the pulsing blood in your ears. You can’t remember when you were in a place this quiet. You start breathing more deeply. Your shoulders drop down lower and away from your ears. You feel at peace.
And then the dirtbikes show up.
Noise is one of the least-recognized forms of pollution that people cause. And we cause a lot of it. According to a study done last year by the National Park Service, human activity has radically changed the way the landscape sounds over about half of the 48 contiguous states. Eastward of the Plains states, it’s hard to find large areas where the average ambient noise level is below 40 decibels (dB).
That’s about the background noise level of a quiet neighborhood with lots of trees. That sounds pretty good, until you remember that it’s the background noise level, the combined low roar of all the noisy human activities within a few miles, and that individual annoying sources of noise are added to that. A loud whisper can reach about 40 dB. Imagine someone loudly whispering next to you 24 hours a day. With background noise levels of 40dB, you’re getting into the range that’s been established to interfere with sleep in some people. And that’s an average: half the time, the background noise will be louder. It doesn’t need to get a whole lot louder before stress, depression, and long-term cardiovascular complaints can result. Studies indicate that a sixth of Americans 20 and under may have permanent hearing damage from exposure to artificial noise.
Those ailments don’t just affect people. Wildlife suffers from human noise as well, whether it's due to stresses similar to those humans experience, or inability to be heard over the din when making sounds used for mating or territorial display, or even abandoning otherwise suitable habitat because human noises are just too prevalent.
Wildlife can also suffer hearing loss from loud noises, even if those noises don’t go on for long. The desert kangaroo rat provides a good example. The rat’s hearing is so sensitive it can detect a sidewinder — a main kangaroo rat predator — slithering quietly on sand 15 inches away, which is well out of striking distance for most sidewinders. After being exposed to engine noise at 90 dB about 14 feet away on and off for eight minutes, roughly equivalent to what a rat might experience if an off-road vehicle idled nearby, the rats had trouble hearing sidewinders less than an inch away. The rats in this experiment recovered their hearing, and they weren’t actually in danger of being eaten by the snake, but rats in the wild generally don’t get the opportunity to recover from temporary hearing loss.
And animals that rely on hearing for navigation, like bats, can fare even worse when noise levels get too high.
In the West, fortunately, we’re blessed with a relative absence of noise over much of the landscape. There are noisy areas in urban areas and along the highways that connect them. But across the intermountain West, there are plenty of places where you could walk for miles with a background noise level of 26 dB or less — about a third as loud as the quietest places in Ohio.
It’s not that those places are silent. Far from it. Wind and bird song and the crunching of your feet on the gravel, rainfall and thunder and coyote song are all found in quiet places, and some of them can be pretty loud. But for the most part, aside from those gravelly footfalls, the sounds there aren’t made by humans.
That may seem to be a literally artificial distinction, but it’s important. Noise is defined as unwanted sounds. That’s a very subjective metric. Your dog’s barking may be music to your ears. It ain’t necessarily so for the hundred other households within earshot. Music is a perennially popular example of how one person’s pleasant sounds are another person’s noise.
Across the United States, the majority of noise doesn’t come from barking dogs or Justin Bieber. It’s made by cars, trucks, and other road vehicles. Aircraft also make a significant contribution. Though the actual sound level of a jet cruising 35,000 feet above your ears may be small, it may well be audible over hundreds of square miles at a time. Industrial machinery adds to the urban roar, as do appliances from air conditioning units to leaf-blowers and chainsaws.
Fortunately for Californians, noise pollution isn’t nearly as pervasive here as it is back East. Our cities are as noisy as any others in the country, and in some spots, like Central LA and Long Beach, ambient noise levels can reach “someone’s vacuuming the room while you’re trying to sleep” levels. But even after a century of sprawl, California’s noisy cities are still mainly limited to the coast and the Interstate 5 corridor through the Central Valley. East of the mountains, California has a lot of acreage that’s about as quiet as anywhere else in the Lower 48, with average background noise levels of between 21 and 26 dB.
The parts of California with background noise levels averaging 26 dB or less are where you might expect to find them: they run in an archipelago stretching from the Chocolate Mountains in eastern Imperial County (where the Navy’s bombing range was apparently figured into the average by the Park Service) through the eastern reaches of Joshua Tree National Park and the Mojave National Preserve, up into Death Valley National Park and the White Mountains to its north. The Twentynine Palms Marine Corps base and the U.S. Army’s Fort Irwin make up most of the remainder.
And this leads us to the real secret for getting to California's quietest places. A look at the map above will reveal that the darkest blue patches in California, which correspond to the quietest places, are separated by thin lines of a lighter color. You can find the full-resolution map here if you really want to drill down.
Those lines are roads. They're considerably noisier than the surrounding countryside. One snakes through Death Valley, meets other roads in the north, then angles westward toward the Owens Valley. That's the main road through the Park. Similar bright loud roads traverse through the Mojave National Preserve, the Mojave Trails National Monument, and Joshua Tree NP. They can be as much as ten decibels louder than the countryside a mile or so away, and in the most obtrusive possible way: the sound of engines approaching from a long way off, passing loudly, then dwindling.
In other words, the secret to reaching California's quietest places is to park your car safely, turn it off, get sufficient water, food, and clothing out of the trunk, then walk away from the road for an hour or two.
If you've lived in a noisy city for a while, the contrast can be stunning. About 25 years ago I was camping on the east shore of Pyramid Lake north of Reno, Nevada, another area with average noise levels below 26 dB, and likely below 20. It was a windless, cool day. It was quiet. It took about an hour for my brain to edit out the sound of my pulse in my ears, and what was I left with? My breathing. The raspy rubbing sounds of my cotton T-shirt. The occasional clatter of big sand grains when a sagebrush lizard stretched out a leg. After another hour, I heard what seemed a phenomenally loud sound, growing louder, as if someone was slamming and re-slamming a door. It was a lone raven at least a half mile away, near the foot of the Lake Range. The sound was the still air rushing through the raven’s feathers as it made leisurely wingbeats, not really trying to get anywhere.
That quiet a landscape can be a little unnerving. People feel confronted by the relative silence. It’s no accident that a common piece of online slang for ominous silence is “*crickets*”: when all you hear is the stridulating chorus of insects, there’s something terribly wrong.
I made the recording below on a night that was one of the best in my life. I was atop Cima Dome in the Mojave National Preserve. I had spent the day hiking through Joshua trees, watching golden eagles through binoculars as they soared on thermals over the Ivanpah Valley, and drinking excellent coffee. What I heard here was incredibly comforting. I was surrounded by an ecosystem, embedded in it, enfolded in it.
Quiet landscapes are increasingly endangered. As industrial society expands, and more things like industrial renewable energy facilities, air traffic routes, new highways, and above all more people are brought to the desert, it's going to be harder and harder to find places where you can go twenty minutes without hearing human noise.
That's not just true in California. Nature sounds recordist Gordon Hempton, who has been tracking the issue of encroaching human noise for decades, said in 2010 that there were by then fewer than a dozen places in the Lower 48 where he could record 20 minutes of natural sound without one human-caused sound intruding. Here he is describing one of the few remaining such places, in Olympic National Park, now the focus of his "One Square Inch" noise pollution awareness campaign:
The good news is that while noise is among the most pervasive forms of pollution, it’s also one of the easiest to reduce. All you have to do is not make more noise. To be sure, our own personal choices won't make air traffic and interstate highways go away any time soon, but there are plenty of sources of noise we do have control over.
My neighborhood offers an example. One complaint my neighbors here in Joshua Tree frequently make about tourists is the noise they bring. It’s unlikely most of those tourists intend to make noise. In the city, you can tame the overwhelming noise by masking it with a boombox. In the Mojave, that same boombox can change the sonic landscape over a square mile, even if the volume isn’t turned that high. There’s nothing to mask the sound, so it travels. I’ve been surprised by mysterious noise on the trail only to meet a hiker wearing earbuds, likely assuming she was thoughtfully keeping her tunes to herself.
Of course, some visitors do seemingly intend to create noise, as witness one young man I saw inside Joshua Tree National Park, pulled over at one of the main road’s many paved shoulder parking areas, with an electric guitar and an amp plugged into his cigarette lighter. He probably meant well, despite altering others’ experience of the Park and breaking the law besides.
It’s a matter of education, and that education comes only through experience and observation. Pay attention to how sound travels in the desert. If you’re with a group of friends, excuse yourself for a bit and walk just until you can’t hear them anymore. It may surprise you how long it takes. When you hear a bird song, note how distant the bird is. Eventually you’ll start to get a sense of how loud you can be without changing the desert soundscape for miles around. (Answer: not very, unless there’s a windstorm.)
And there's this: unless you’re planning to camp surrounded by idling off-road vehicles, leave the amplified music at home. You might be surprised at the living music you’re able to hear without it.