A worldwide phenomenon, “The Hum,” remains a mystery. Generally described as a low-frequency droning or pulsing sound, it is often compared to the sound of a distant diesel engine.
For the small percentage of people who can hear the noise at any given location, it can become quite disturbing, sometimes leading to suicide.
If I possessed marketing savvy, I would embellish this story (and most of the posts in this blog) with conspiratorial claims, “rock-solid evidence” of alien visitors, or secret lore channeled through my Cherokee shaman grandfather. But I prefer being true to the stories, even if most people are drawn to gimmicks.
And, fortunately, there is a “Hum” researcher who tries to play it straight, as well. Dr. Glen MacPherson has compiled a map showing thousands of reports of the odd, droning sound. And he has invited discussions on evidence-based theories about “The Hum.”
Among the possible explanations: tinnitus or other disturbances of the auditory system, the mating call of the midshipman fish, mechanical devices, industrial processes, meteorological sources, and geological anomalies.
Rumbling Bald Mountain
Back in the 1800s, reports emerged from various spots in the mountains regarding unusual sounds: drones, bangs, booms and rumbles. Bald Mountain, in the Hickory Nut Gorge near Chimney Rock, acquired the name “Rumbling” Bald Mountain after earthquakes in 1874.
I’ve written about this in the past and will be revisiting this incident in a future post. But, in short, the State Geologist, W. C. Kerr described the origin of the rumblings:
The basal rock, which occupies the bottom of the gorge, and forms the principal material of the escarpment beneath the vertical cliffs, is a soft, friable, horizontal, thin-bedded gneiss, which easily weathers and crumbles down, and is swept away by the stream. The jutting, solid masses above being unsupported, break off in huge sheets and massive blocks, and either slide down the face of the cliff with a grinding movement or topple over and go thundering down the steep slopes often for half a mile or more, with much jarring and commotion, frequently shaking the earth for miles around.
Several years later, other strange, loud noises were reported in the vicinity of Rabun Bald, Georgia near the North Carolina border.
Macon County, NC resident Barry C. Hawkins submitted this story for the Monthly Weather Report on October 8, 1897:
There are several instances of sounds in nature, for which no reasonable or proved explanation can be found and, probably, the most remarkable of these is the phenomenon known as the “barisal guns.” The facts relating to these seem to be as follows: At a certain point near the seacoast in India, sounds are heard resembling distant cannon firing. These sounds have been extensively studied, but no reasonable hypothesis has been advanced which accounts for the “guns.” [The unexplained explosive sounds were heard on the delta of the Ganges River.] Mention has been made in the MONTHLY WEATHER REVIEW of certain sounds heard on Black Mountain, N. C., in 1876, and obviously caused by the slow falling or sliding and crushing of rocks.
But I am going to describe a phenomenon which seems to be very similar to the famed “barisal guns,” and located right in the United States. No account of these sounds has ever been published, and no scientist has ever taken the slightest interest in them, or paid any attention to them, so far as the writer knows.
In northern Georgia, in the extreme north of Rabun County, close to the North Carolina State line and thirty-fifth parallel of latitude, is Rabun Bald Mountain, forming one of the highest peaks on the very crest of the Blue Ridge. This mountain has the same bulky shape and long rambling ridges running for miles in all directions as are spoken of by Hugh Miller as characterising the gneissic mountains of Scotland.
On the east side there is a small cliff over which a small stream falls in wet weather, and from the ranges to the east the peak appears in form exactly like a brace. The entire mountain is of gneiss. Now, on this mountain are heard mysterious sounds resembling distant cannon firing, and these sounds have been heard for many years, probably at least fifty; they have been heard in all kinds of weather and at various points on the mountain.
Numerous observers have noted the sounds, and two reliable gentlemen once spent a night on the summit. About 10 o'clock p. m., sounds were heard which were supposed to be cannon firing in Walhalla, S. C., in celebration of the presidential election, this being in November, 1884; but soon the sounds were found to issue from the ground and from a ridge to the southwest of the mountain. The explosive sounds continued till late in the night. At times they seemed to proceed from the ground immediately under the observers.
In early days when bears were plentiful the pioneers said the sounds were caused by these animals rolling small boulders off the mountain sides in search of worms, snails, etc., but the bears have passed and the sounds still continue. Later the sounds were ascribed to “harnts” (haunts or ghosts); two men were murdered in “the sixties" and buried at some unknown point on the “Bald.” Some have heard these sounds so near them in the woods that the sound was like that of a falling tree. But ordinarily the sound is like distant firing, as noted above. They are not heard at all times, people having spent the night on the peak and heard nothing. The writer can verify all the statements made above. They are strictly true, and it is with the hope of calling the attention of scientific men to the subject that I present this brief account of the mystery of a mountain.
In the 1870s, sounds wafting around Roan Mountain, on the North Carolina/Tennessee border, more closely resembled “The Hum.”
Henry Colton had travelled extensively around the Southern Appalachians, but the “mountain music” he heard on Roan was one of the most inexplicable phenomena he ever experienced:
In the month of July, 1878, I spent several weeks at the Cloudland Hotel on Roan Mountain, in Western North Carolina, which is 6387 feet above the sea-level. On the eastern side of the Roan Mountain range is a kind of rough table-land about 2000 feet lower than the summit of that mountain. On the west the mountain descends into the East Tennessee Valley, which may be said to be about 4000 feet lower than the same point. The land on the top of the Roan is singularly free from tree growth, the Canada balsam coming to a certain elevation and there ceasing. The somewhat level top is covered with a luxuriant growth of grass. I give this description as preliminary to what I intend to relate. The hotel is on a plateau near a glen, between two peaks somewhat higher than the general top of the mountain.
Several of the cattle-tenders on the mountain and also General Wilder had spoken to us about what they called “mountain music.” One evening they said it was sounding loud, and Dr. J. T. Boynton, of Knoxville, Hon. M. Thornburgh, and myself, accompanied General Wilder to the glen to hear it. The sound was very plain to the ear, and was not at all, as described, like the humming of thousands of bees, but like the incessant, continuous, and combined snap of two Leyden jars positively and negatively charged. I tried to account for it on the theory of bees or flies, but the mountain people said it frequently occurred after the bees and flies had gone to their winter homes, or before they came out.
It was always loudest and most prolonged just before there would be a thunder-storm in either valley, or one passing over the mountain. I used every argument I could to persuade myself that it was simply the result of some common cause, and to shake the faith of the country people in its mysterious origin; but I only convinced myself that it was the result from two currents of air meeting each other in the suck between the two peaks, where there were no obstruction of trees, one containing a greater, the other a less amount of electricity, or that the two currents coming together in the open plateau on the high elevation, by their friction, and being of different temperatures, generated electricity. The "mountain music" was simply the snapping caused by this friction and this generation of electricity. Many have noted the peculiar snapping hum to be observed in great auroral displays, particularly those of September 1859 and February 1872.
As the amount of electricity in the air-currents became equalized or surcharged, they, descending to either side, caused the thunderstorms usual every day in the valleys near the mountain, and sometimes immediately on the edge of the timber surrounding the great bald top. The air-currents of the Western North Carolina mountains and the East Tennessee Valley form an aerial tide, ebbing and flowing. The heated air of the valley rises from nine in the morning until three or four in the afternoon, making a slight easterly wind up and over the Roan Mountain. As night comes on the current turns back to the valley, almost invariably producing a very brisk gale by three or four o'clock in the morning, which, in its turn, dies down to a calm by seven, and commences to reverse by nine o'clock. This continual change of the currents of air makes it an impossibility for any great malarial scourge to exist in the East Tennessee Valley, especially its north-eastern end.
The Roan Mountain is one of the curiosities of nature. It is a part of the great range formed of metamorphic rocks which border on the true silurian formation from the Canadas to Alabama; though not so high as the Black Mountains, in the same county, it and many others of the same range present a peculiarity not known to those higher peaks of the eastern range. This peculiarity is the vast tracts of land entirely devoid of trees and mostly covered with a luxuriant grass, much loved by cattle. The highest range of the thermometer, an accurate government instrument at the hotel, during the past summer, was 74°.