How should we assess such calamities and disasters?

Worship consists in fact of two kinds, positive and negative. What is meant by the positive is obvious. As for negative worship, this is when one afflicted with misfortune or sickness perceives his own weakness and helplessness, and turning to his compassionate Sustainer, seeks refuge in Him, mediates upon Him, petitions Him, and thus offers a pure form of worship that no hypocrisy can penetrate. If he endures patiently, thinks of the rewards attendant on misfortune and offers thanks, then each hour that he passes will count as a whole day spent in worship. His brief life becomes very long. There are even cases where a single minute is counted as equal to a whole days worship. (The Flashes, 2. Flash)

Patience is one of the worshipping responsibilities that Apostle of God (peace be upon him) performed perfectly. He (pbuh) passed the test of patience with having emigrations, wars, misfortunes, and difficulties in the most advanced meaning.

Namaz (ritual of worship centered in prayer) is the Miraj (miraculous ascension to the throne of God) of a believer. Misfortunes and sicknesses are different ascension stairs. A Muslim ascends spiritually as he submits to every command of God and as he avoids forbidden. Patience, in the cause of misfortunes and sicknesses is another way of this ascension. The misfortunes that a person experiences teach him how incapable of himself in the presence of misfortunes such as traffic accidents, floods, and storms. A human who understands that he is incapable of controlling incidents, which occur in his own body as external influences, after taking necessary treatments, with the conscious of knowing not being the owner of himself trusts his God and looks for cure from Him. This aspect is a great development for a believer.

Humans, having different tests throughout their lifetimes, after a brief world life will turn back to realm of eternity. They will be re-united with the essentials of the shadows and they will find and experience benefactions of Marifat (communion with the God) and affection for God in the most perfect form in there.