Matsya Purana — The Devasura War: Tumult
वृष्टिरत्यद्भुताकारा गगने समदृश्यत संप्रच्छाद्य दिशः सर्वास् तमोमयमिवाकरोत् //
vṛṣṭiratyadbhutākārā gagane samadṛśyata saṃpracchādya diśaḥ sarvās tamomayamivākarot //
A rain of utterly wondrous form appeared in the sky; veiling all the quarters, it made them seem as though they were fashioned of darkness.
It portrays pralaya as beginning with extraordinary, unnatural rain that blankets the entire horizon, a classic Purāṇic sign that the ordered world is being overwhelmed and obscured.
As an omen-verse, it implies the dharmic need for vigilance and preparedness in times of calamity—leaders and householders should protect dependents and preserve sacred duties when cosmic disorder manifests.
No direct Vāstu or ritual procedure is stated; the key takeaway is the omen of total obscuration (darkness-like rain), which in ritual reading signals an inauspicious, transitional time requiring protective observances rather than construction activity.