The real potential and scope of the recent flooding around Boulder, Colorado is readily apparent in this interactive map:
The red spots on this Google Map, prepared by Cascadia, represent structures within the FEMA floodplain or within 50 ft. of any stream or drainage/irrigation ditch. As you zoom in on the map, you can begin to see individual structures. Given these parameters, many structures will not be touched but the total number (from City of Boulder GIS data) tops 5000 buildings, large and small.
The people of Boulder will be in need of assistance for some time to come. You can help through your service or contributions by visiting Boulder Flood Relief.