BFB, on 20 December 2011 - 12:35 PM, said:
You saw a contrail at 4000 feet on a very hot day?? Was it over 30c? If so very strange but not impossible.
yes many times during summer months, it was clearly less than a mile away since i could make out detail on the plane (no way to make out detail at contrail altitudes), very thick trail almost like smoke, fans out to form a cloud eventually turning the sky white and hazy. possibly 30C, maybe 25C, but a hot summers day, had relatives with me so I do not misremember the conversations, nor misremember the time and dates. had it independently confirmed by others who reported the same unusual thing from other locations (with no prompting from me), seen it on many occasions. you can say its possible, but what I saw is not possible in my opinion without some out of the ordinary means. I have never seen anything like that, then suddenly after decades of not seeing anything like it they start appearing and everyone I know notices. so something changed. couple that with aircraft observations, flying from horizon to horizon and back again leaving these thick trails, aircraft travelling in pairs one behind the other, low altitude, off known flight routes (when you live under a flight route near an airport you know the routes), the set times these trailers appear, always in front of the sun, their unsual landing sequence low over me, their unsual (non commercial) appearance, etc, etc. these are my own observations.
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btw the average height for water vapor to freeze is not 30.000 feet is around 2-3 km.
25-30,000 feet is the often reported height for visible contrail formation.