The restricted flow of waters from cataclysmic floods from Glacial Lake Missoula, and pluvial Lake Bonneville through the constriction of the Wallula Gap in the Horse Heaven Hills flowed into south-central Washington and north-central Oregon, and were backed up by the Columbia River Gorge, forming Lake Condon. The water remained for a period of 5-7 days before the flood waters drained through the Columbia River Gorge. Lake Condon reached an elevation of about 1200 feet above sea level (today's sea level) before subsiding.