Brihat Samhita
अशुभऽकृतिघनगन्धर्वनगरनीहार धूमपांशुयुता । प्रावृषि करोत्यवग्रहं अन्यर्तौ शस्त्रकोपकरी ॥ ३०-२१ ॥
If during the rainy season the twilight hours should be marked by the appearance of clouds shaped maletically, if the clouds should assume shapes known as Gandharvanagara (air-castles), and if the sky should be filled with snow, dust and smoke, there will be drought; if the same things should occur in any other season, there will be wars in the land.
english translation
azubha'kRtighanagandharvanagaranIhAra dhUmapAMzuyutA । prAvRSi karotyavagrahaM anyartau zastrakopakarI ॥ 30-21 ॥
hk transliteration by Sanscript