More than half (54%) of the flood-prone area is located in the Sava River Basin in central Slovenia, 42% in the Drava River Basin in the east, and 4% in the Soca River Basin and rivers directly flowing to the Adriatic Sea in the west. About 30 extensive flood-prone areas (approximately 237 000 ha) lie in the broad areas of alluvial plains, which in many places have been converted to cultivation and in some places housing. Torrential floods, which occur mostly in the mountains or hilly areas, are short in duration but violent.