The video above is from the vigil for the feast of the Transfiguration on Mount Tabor, while the one below shows the moment the Holy Cloud appears.
The 2017 video above of the Holy Cloud is a bit difficult to see. The video below from 2015 gives a better view of the Holy Cloud of Tabor, which appears annually on Mount Tabor only during the vigil for the feast of the Transfiguration at the Greek Orthodox Monastery there, during the Old Calendar reckoning of the feast on August 6/19th, since the Patriarchate of Jerusalem follows the Old Calendar.