Qur'an 69:7

سَخَّرَهَا عَلَيْهِمْ سَبْعَ لَيَالٍ وَثَمَـٰنِيَةَ أَيَّامٍ حُسُومًا فَتَرَى ٱلْقَوْمَ فِيهَا صَرْعَىٰ كَأَنَّهُمْ أَعْجَازُ نَخْلٍ خَاوِيَةٍ

Which He imposed on them for seven long nights and eight long days so that thou mightest have seen men lying overthrown, as they were hollow trunks of palm-trees.