Haew Narok Waterfall is the highest in Khao Yai This is the highest waterfall in Khao Yai. It cascades over three levels with the final level hurtling 80 meters into a deep abyss. At the height of the rainy season, this waterfall is a truly fearsome sight. In fact, almost every year at least one elephant loses its life after slipping into the treacherous water.