In Boulder, Colo., at the end of September, you could virtually map the contours of the floodplains by measuring the piles of household debris left on the curb for the trash man. On the top of a rise, the curb would be clear. Twenty yards down the hill, a battered bookcase, a cluster of soggy and soiled towels. As you walked farther down the street, larger piles would appear—sofas, box-spring mattresses, dolls and dollhouses, ruined stuffed animals. Piles and piles of them, the piles getting larger as you reach the base of one hill, then repeating the pattern in reverse as you climb the next one.
It started raining on Sept. 10, and then it kept up pretty much nonstop until the 13th. And it rained hard, reaching about 1.2 inches an hour on Sept. 12. An area that usually gets about 12 inches of precipitation in an entire year got nearly 17 inches in less than a week. According to an early report prepared by CIRES at the University of Colorado, “Boulder’s COOP weather station (since 1893) set records for one-day (9.08 inches), two-day (11.52 inches) and seven-day (16.9 inches) totals; the previous one-day record was 4.80 inches and previous one-month record was 9.59 inches.”