The deluge caused American Falls Lake to breach its natural lava dam, which was rapidly eroded with only the American Falls left in the end. The flood waters of Lake Bonneville, approximately twenty times the flow of the Columbia River or 5 million ft3/s (140,000 m3/s), swept down the Snake River and across the entirety of southern Idaho. For miles on either side of the river, flood waters stripped away soils and scoured the underlying basalt bedrock, transforming the region into channeled scablands forming the Snake River Canyon and creating Shoshone Falls, Twin Falls, Crane Falls, Swan Falls and other waterfalls along the Idaho section of the river. The Bonneville flood waters continued through Hells Canyon and eventually reached the Columbia River. The flood widened Hells Canyon but did not deepen it. As the Bonneville Floods rushed down the Snake River, the Missoula Floods occurred in the same period, but originating farther north. The Missoula Floods, which occurred more than 40 times between 15,000 and 13,000 years ago, were caused by Glacial Lake Missoula on the Clark Fork repeatedly being impounded by ice dams then breaking through, with the lake's water rushing over much of eastern Washington in massive surges far larger than the Lake Bonneville Flood. These floods pooled behind the Cascade Range into enormous lakes and spilled over the northern drainage divide of the Snake River watershed, carving deep canyons through the Palouse Hills including the Palouse River canyon and Palouse Falls. The Lake Bonneville Floods and the Missoula Floods helped widen and deepen the Columbia River Gorge, a giant water gap which allows water from the Columbia and Snake rivers to take a direct route through the Cascade Range to the Pacific. The massive amounts of sediment deposited by the Lake Bonneville Floods in the Snake River Plain also had a lasting effect on most of the middle Snake River. The high hydraulic conductivity of the mostly-basalt rocks in the plain led to the formation of the Snake River Aquifer, one of the most productive aquifers in North America. Many rivers and streams flowing from the north side of the plain sink into the aquifer instead of flowing into the Snake River, a group of watersheds called the lost streams of Idaho. The aquifer filled to hold nearly of water, underlying about in a plume thick. In places, water exits from rivers at rates of nearly .