Tree falls in the forest etc etc ... “The Sahara is as large as the United States, and there are very few weather stations,” he added. “So it’s ridiculous to s

Tree falls in the forest etc etc ... “The Sahara is as large as the United States, and there are very few weather stations,” he added. “So it’s ridiculous to say that this is the first, second, third time it snowed, as nobody would know how many times it has snowed in the past unless they were there.” "Not observed by a human" does not mean "did not happen". Humans measured things where humans lived or traveled during almost all of their existence. E.g., see Giarabub[1]. The methods we have today of inferring past events from remaining physical indicators tend to mash together decades to hundreds of years of events. One must keep these things in mind. [1]: http://climate.unur.com/ghcn-v2/124/62176.html http://climate.unur.com/ghcn-v2/124/62176.html