"The most dangerous and alarming feature of the situation was the cutting back of the torrents as they rushed down the delta slope toward the Salton Sea. The fine silt of which the soil was composed washed out like sugar, and wherever there happened to be a strong current, the flow soon produced a rapid. The rapid then became a cascade, the cascade grew into a fall, and the fall finally developed into a roaring cataract, which 'cut back', upstream, at the rate sometimes of 4,000 ft a day, widening as it receded, and leaving below it a deep gorge with almost perpendicular walls. Some of the gorges were 50 to 80 ft deep and more than 1,000 ft across. It was estimated that the channels thus formed during the floods of 1906 had an aggregate length of more than 40 miles, and that the solid matter scoured out of them and carried down to the Salton Sea was nearly four times as great as the whole amount excavated in the digging of the Panama Canal. The total of 400,000,000 to 450,000,000 cubic yards were moved. Mr. Cory stated: "Very rarely if ever before, has it been possible to see a geological agency effect in a few months a change which usually requires centuries." --George Keenan, quoted in The Periscope, a publication of the Coachella Valley Historical Society, 1995.