Checking the math, using Google Earth and the time & date website.   My measurement from witness to target was 1500 feet (500 yards, or just over 4 football fields away when you include the end zones). There is a slight elevation advantage for the witnesses of about 4 feet, plus some more if they were elevated in a pick-up truck.   They left themselves some wiggle room by saying it was between 5:00 and 5:30 PM; given that the encounter was only 15 seconds, I'm surprised no one looked at their cell phone or the dashboard clock to get an exact time.  Civil twilight was 6:18 near Silo, OK, on the date of the encounter.  Civil twilight is when the sun sets; there's still some usable daylight left even after civil twilight.    The witness's statement is self-contradictory - first she (based on her reporting that her husband had a separate encounter) says that the "Bigfoot" was walking when first seen.  Then she says the "Bigfoot" stopped but doesn't say anything about the "Bigfoot" crouching or laying down for concealment.  Then she says the "Bigfoot" got up and continued walking.   The Guinness Book of World Records states that the normal (intelligible) outdoor range of the male human voice in still air is 590 feet, 6.6 inches.  This woman was screaming at a "Bigfoot" almost three times that distance away, with a slight wind.  It seems unlikely that her shouting attracted the "Bigfoot's" attention.  Perhaps the human odor or the vehicle engine alerted whatever it was.   The witness says that it was "a little windy;" the investigator interprets this as "very windy."     The line of sight to the target does seem fairly open - apparently, Oklahoma is not lush and verdant everywhere.  But like you, I am less sanguine about accepting the veracity of such a long distance sighting.     Anyone who is a passenger in a vehicle on an Interstate can test this a little bit.  Watch for the 1/10 of a mile road signs (in most states, they're small rectangles).  When you see a #.8 mile marker, guess at the height of an object up the road a bit.  (There's probably an easier way to find a place where you can see a 1/4 mile over relatively flat land to get a feel for the distance, I just can't come up with it right now.)    

On Bigfoot and Beyond, Cliff and Bobo recently talked to the woman who runs the Bigfoot Data Project.  She is apparently looking at as much data on claimed Bigfoot encounters as she can from a very stringent scientific viewpoint.  So when evaluating height, she had her minions (or minion) do research on how fear or apprehension affects the estimation of height - no surprise, the more afraid you are the bigger something looks.   I'm not going to try to recap what she said beyond that, but it was a good episode, probably within the last 50 or so. 

If I had a dollar for every person that said that black tailed deer stood about five feet tall and weighed three-fifty or that a coyote was about four feet tall and about seventy pounds, I would be rich. Deer and coyotes are not as high  nor weigh as much, as people imagine them to be. The same could happen in the opposite. People under estimating them. People are surprised to find out a wild turkey can weigh as much as 30 pounds or that a golden eagle weighs as little 6 to 15 pounds. informed, experienced perception is important.

I just came across this BFRO report: https://www.bfro.net/gdb/show_report.asp?id=79845   Short story shorter: 3 witnesses reported seeing a Bigfoot in Oklahoma walking off a powerline easement from more than 1,500 feet away.    I'm not a field researcher but 1,500 feet away, across a river, windy conditions, late afternoon, and down a powerline cut area do not seem like good conditions for clear observation. Any researchers on here who are comfortable with BFRO referring to this as a "Triple A" sighting? If so, why?   I'm not challenging what the witnesses reported seeing. I just think from an evidence perspective that a Class A designation is a bit ambitious.

I explored the science behind height estimates a while back. Basically there are 3 factors that affect accuracy :  1) The actual height of the target (in this case, a Bigfoot).  2) The height of the witness. This is referred to as the own-anchor effect, where the witness may use their own height as an anchor or benchmark from which to form a judgement on the target’s height. 3) The witness’s knowledge of, or expectations about, the average height of the target’s population.   Much of this science comes from research into eye witness testimony, so it's questionable whether we can apply it to Bigfoot reports. The consensus among eye witness researchers seems to be that witnesses typically under-estimate the target's height. I think for Bigfoot reports, #3 above is most critical. The statement "it was 7-8 ft." is so common in reports it's like one of the given letters from Wheel of Future before the contestant even picks their own letters.    @Doug touches on what could be a fourth factor specific to Bigfoot height estimates -- the witness's knowledge of and experience with other large animals in the forest.    Here's my post on Substack for those interested in a deeper review of the science.