Lama Norbu Töndrup was Kalu Rinpoche’s root lama and retreat master during his three-year retreat at Tsadra Rinchen Drak.
Lama Norbu Töndrup had first been a monk at Palpung Monastery. Then because of his great qualities of meditator, he was appointed by the 11th Situpa (Situ Pema Wangchuk, 1886-1952) as retreat master (drüpön), function he held during 12 years. From then on, he only spent his life in retreat. Kalu Rinpoche wrote : "Since he was 40 until he passed away, he had only been living in retreat. At 70, he rooted out all the attachments to worldly appearances, merging the states of meditation and post-meditation. At 74, his mind dissolved in the sphere of reality, and being left as a relic, his body took the appearance of a 8 years old child. When the mandalas of the four great tantras were opened and the body offered to the fire, many rainbows appeared during the whole day and some cinerary pills (rilbu, shariram) of various colors were found. These different signs shew very clearly that he really reached the state of the Great Non Meditation according to the Mahamudra terminology or the Great Exhaustion of Reality itself beyond intellect according to the Dzogchen terminology." That is to say he reached the level of buddhahood.
During the funeral ceremonies that Kalu Rinpoche was leading, his heart was not burnt by the fire and was kept in a stupa. Besides the cinerary pills and the rainbows, a rain of flower did happen. The present Situ Rinpoche spoke about that, having himself beeing told that event by an eyewitness. The sky was clear. Nevertheless small drops made of coton and containing water were falling down. The sun was reflecting on them, giving an impression of rainbow flowers. Once these drops reached the ground, a thin downy substance would eventually be left on the floor.
The facts that his body got smaller to reach a child size and that rainbows appeared in the sky over the pyre show that he reached the rainbow body.
According to Situ Rinpoche, this was not uncommon in Tibet but rains of flowers were really exceptional "like a white elephant" he said.