The disappearance day of Srila Prabhupada is observed by his followers by offering prayers to him and feeling his separation. Simultaneously, heartfelt gratitude is also expressed to please his divine grace and seek his blessings.

CC Madhya 8.248, Translation and Purport

The spiritual hankering and lamentation become manifested in the form of the thirst for the association of a pure devotee and the tears shed in their separation. 

There is the following statement in the Bṛhad-bhāgavatāmṛta (1.5.44):

sva-jīvanādhikaṁ prārthyaṁ śrī-viṣṇu-jana-saṅgataḥ

vicchedena kṣaṇaṁ cātra na sukhāṁśaṁ labhāmahe

“Out of all kinds of desirable things experienced in the life of a living entity, association with the devotees of the Lord is the greatest. When we are separated from a devotee even for a moment, we cannot enjoy happiness.” 

Śrī Caitanya Mahāprabhu asked, “Of all kinds of distress, what is the most painful?” Śrī Rāmānanda Rāya replied, “Apart from separation from the devotee of Kṛṣṇa, I know of no unbearable unhappiness.”.

(Srila Prabhupada Lilamrita Vol. 6)

November 14, 1977, at 7:30 p.m., in his room at the Krishna-Balaram Mandir in Vrindavana, Srila Prabhupada gave his final instruction by leaving this mortal world and going back to Godhead.

Ācārya means one who knows the purport of the sāstra, and he behaves himself according to the shastric regulative principle and teaches his disciple in that way. Ācārya means whose behavior, whose activities should be followed. That is called ācārya. Being the founder acarya of ISKCON, Srila Prabhupada continued teaching us with his own example.

“His departure was exemplary because his whole life was exemplary. His departure marked the completion of a lifetime of pure devotional service to Krishna. A few days before the end, Srila Prabhupada had said he was instructing as far as he could, and his secretary had added, “You are the inspiration.” “Yes,” Srila Prabhupada had replied, “that I shall do until the last breathing.”

Srila Prabhupada’s departure was glorious because he remained in perfect Krishna consciousness, chanting and hearing the holy names of Krishna.” 

(Following Srila Prabhupada.- A Chronological Series by Narada Muni Das)

It is true that the words of the spiritual master are more important than the vapu or physical presence. Nevertheless, devotees feel the separation as revealed from the following excerpt:

“I remember when Srila Prabhupada was getting ready to leave Los Angeles to go back to India and he wasn’t feeling well; and that’s when Srila Prabhupada spoke to us for the first time about vani and vapu, how vani is a much more intimate association with the spiritual master than just associating with his physical form. But being absorbed in both hearing and executing his instructions and his teachings links the disciple in a much more intimate way with the spiritual master, in an eternal way rather than a temporary way. So Srila Prabhupada spoke on that and, of course, it was very encouraging to hear it, but at the same time it was very sad as we felt great separation.”

Giriraj Swami 

Giriraj Swami in his talk, Remembering Srila Prabhupada on his Disappearance Day said:-

“Prabhupada spent his last three days with his disciples at the Krishna-Balaram Mandir, and the last day he didn’t speak. His only words were in the morning, when the kaviraja asked him to drink some juice and he replied, “Meri kuch iccha nahin”: “I have no desire.” After that, Prabhupada didn’t speak. He was in a completely internal state of consciousness, and the devotees surrounded him with kirtan. For the last few hours, in the afternoon, the leaders opened up the doors to everyone. Young, old, children, men, women—all were allowed to be in the room with Srila Prabhupada and to reciprocate love with him. Then, at about 7:26 p.m., his tongue and mouth moved—Hare Krishna—and he left.

So there is always that question: Do we want the kingdom of God without God, without God’s representative, or do we want the kingdom of God with God, with His representative, as their humble servants? And so I pray to Srila Prabhupada that I will always remember this lesson and always pray and act in such a way that he will be pleased to stay with each of us individually and all of us collectively, and bind us to his lotus feet eternally.” 

(Memories Anecdotes of a Modern Day Saint – Vol. 3 by Siddhanta Das)

If we truly follow his instructions then as said by him in the following excerpt, he will constantly communicate with each and every one of us in a very beautiful way.

One devotee said, “But Srila Prabhupada, we are crying because we can’t be without you and when you leave, we won’t know how to communicate with you.” Prabhupada said, “I will communicate with you through your heart. I will come to you in your dreams. I will communicate with you through dreams as caitya-guru.”

All glories to Srila Prabhupada.