The Infrasound Theory
On the Smithson tape, Cassidy Daniels mentions sheltering in a small hut or shack attached to an antenna with Carrie Mercer. This has, for some, opened the possibility that such a transmitter close to the site of the tragedy may have been wholly or partially responsible for it.
These theories rely on research suggesting that extremely low-frequency sounds, sometimes known as infrasounds, can cause feelings of paranoia or awe as well as other unusual behavior in human beings. Some researchers have suggested that such infrasound could also result in sleeplessness, irritability, panic attacks, or even physical sickness, nausea, or vomiting. Indeed, infrasound is often raised as a possibility in explaining the Dyatlov Pass Incident, a similar mystery in the former Soviet Union.
During the Cold War, several sites in the USA and USSR hosted extremely powerful over-the-horizon radar transmitters and receivers, which have been linked in several reports to infrasound and other sorts of harmful microwave radiations. Is it not possible, then, that one such site in Utah had that effect on the hikers, perhaps also explaining the hallucinations that led Carrie Mercer to wander away and presumably die in the wilderness?
As with all the Sagebrush Mountain Incident theories, this one has several problems. First, there were never any OTH radar transmitters or receivers in Idaho; they were all built in Alaska or Maine. Second, there is no record whatsoever of any antenna or antenna-like structure on or near Sagebrush Mountain in 1997. Adherents of the theory claim that it’s plausible such an array was top-secret and left off maps, possibly even dismantled in haste after the incident. But no such structure has appeared in any contemporary satellite photographs until cell phone towers were erected in the area starting in 1999. Those did often have an associated equipment that hut, but were clearly far too late to have any effect.
While infrasound can be generated naturally from phenomena such as a Kármán vortex street caused by high winds, this is exceedingly rare and even the miserable atmospheric conditions around the mountain in September 1997 do not seem to support it.
As such, this theory also falls apart, and it raises still further questions. Where, exactly, did Cassidy Daniels and Carrie Mercer find shelter during the time between the group’s deaths and Daniels’ rescue if no such antennas or no such shacks existed? And what, if anything, does Daniels’ report of shadowy figures bearing her friend away suggest about this shelter? The official report dismisses this as a hallucination on Daniels’ part, but John Smithson himself is of the opinion that, without a temporary shelter of some kind, Daniels could not have lived long enough to find help in the state that she was found.
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