1951, June 10, August 3, 31

On August 3, 1951, the C. and S. Railroad crossing washes out again, purportedly at Four Mile Canyon Creek.

"Between Longmont and Boulder, several sections of the C. and S. Railroad tracks were washed out. The biggest stretch was about 500 feet of track southeast of Niwot. Another section of C. and S. track just north of the crossing on the Valmont road a short distance east of Boulder was badly damaged..... An unofficial measurement of 3.27 inches of rain was made in North Boulder by District Water Commissioner T. Platt at his home in the 3000 block on 11th St." Daily Camera, August 4, 1951

The Silver Lake ditch was washed out at the Four Mile Canyon Creek crossing, near the current Foothills Housing site. Silver Lake ditch records, Katherine Long Gates

"During the afternoon and night of 3 August, a heavy rainstorm occurred over the frontal range and foothills east of the Continental Divide from the vicinity of Boulder to near Fort Collins, Colorado, a distance of approximately 50 miles. One of the storm centers was in the Left-Hand Creek near the town of Niwot. At this storm center, total precipitation was unofficially reported to have been over 6 inches. The runoff from this storm caused flooding on St. Vrain Creek and on it's tributaries, Dry Creek and Left Hand Creek. Overbank flows occurred along most of the length of Left Hand Creek. Bridges, roads, crops and irrigation structures were damaged." Flood Plain Map for Left Hand Canyon Creek, Corps of Engineers, Jan 1969

Peak discharge at Orodell (located 1 mile upstream from Fourmile Creek and 3 miles southwest of the courthouse in Boulder) : 1220cfs. From US Army Corps of Engineers, August 1969 Floodplain Mapping of Boulder Creek

Compiled by Elizabeth Black