Canto 3 -
Araṇya-kāṇḍa
Chapter 23: Khara Disregards Evil Omens on the Way
Text 3.23.7

प्रभिन्नगिरिसङ्काशास्तोयशोणितधारिणः।
आकाशं तदनाकाशं चक्रुर्भीमा बलाहकाः॥

prabhinna-giri-saṅkāśās toya-śoṇitadhāriṇaḥ
ākāśaṁ tad anākāśaṁ cakrur bhīmā balāhakāḥ

prabhinna-giri-saṅkāśāḥ = appearing like mountains whose wings had been cut by Indra; toya-śoṇitadhāriṇaḥ = showering blood red water; ākāśam = sky; tat = the; anākāśam = dark; cakruḥ = made; bhīmāḥ = the terrible; balāhakāḥ = clouds.

Appearing like mountains whose wings have been cut by Indra, the terrible clouds showering blood red water made the sky dark.1

The clouds made the sky dark by covering it.

1 There is an alliteration in the Sanskrit verse with ākāśam and anākāśam.