Likely, a sudden downpour of rain caused the chariots to get bogged down because of the overflowing Kishon River.
وَيُذَكِّرُنَا هذَا ٱلِٱسْمُ بِٱلْمَعَارِكِ ٱلْحَاسِمَةِ ٱلَّتِي وَقَعَتْ قُرْبَ مَجِدُّو .‏