Matsya Purana — Design and Splendour of Tripura: Maya’s Threefold Moving Fortress
यज्ञधूमान्धकाराणि संपूर्णकलशानि च गगनावरणाभानि हंसपङ्क्तिनिभानि च //
yajñadhūmāndhakārāṇi saṃpūrṇakalaśāni ca gaganāvaraṇābhāni haṃsapaṅktinibhāni ca //
There appear masses of darkness like sacrificial smoke, and also forms like brimming water-pots—shapes that seem to veil the sky, resembling rows of swans.
It does not directly describe Pralaya; instead, it lists cosmic-atmospheric portents—sky-veiling forms and smoke-like darkness—often treated in Purāṇas as warning-signs preceding disturbance in the natural or ritual order.
Such omens guide decision-making: a householder or king performing sacrifices is expected to heed ritual portents, consult learned priests, and correct ritual faults or postpone actions when signs indicate disorder.
Ritually, the imagery points to yajña-environment assessment—smoke, sky-covering haze, and unusual formations are treated as nimittas; in practice this supports choosing a proper time/site and ensuring purity and correct procedure for sacrificial rites.