WSP11466

• File Number: 8441.400
• Description: Colorado Big Thompson Project - Reports
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 12/1/1976
• Author: Gingery Assoc.
• Title: Special Flood Plain Information Report - Big Thompson River and Tributaries - Larimer County CO - Volume 1
• Water Supply Pro - Doc Type: Report/Study

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~31, 1919 - The flood of July 31, 1919 was caused by
a c oudburst a short distance above Drake. The storm
was of such short duration that the mean daily discharge
for July 31 was only 490 cfs, while the peak discharge
recorded for that same day was 8,000 cfs. There were no
records of property damage estimates, but the Loveland
Daily herald of August 1, 1919, stated... "The
road bed was washed out to bedrock. During the worst
of the flood, the entire road bed was covered with 2
feet of water, except at the highest points."

September 1-4', 1938 - The Big Thompson drainage basin
was one of the areas of heaviest precipitation during
the general storm of September 1-4, as reported by
the Weather Bureau. Rainfall accumulation was 2.95
inches at Estes Park and 3.16 inches near Long's Peak.
At the Loveland filter plant, 8.7 inches of rainfall was
reported.

September 10, 1938 - A second storm also occurred in the
foothills area on September 10, 1938. This storm was
basically a cloudburst over many tributaries where flood
flows were of short duration. The major damage from
this flood was to the highway within the canyon, which
was washed out in ten locations.

June 21-22, 1941 - Heavy rains started about 11:00
p,;m. on June 21 and fell for approximately 3 hours along
the Big Thompson River between the Forks Hotel and the
municipal hydro-electric plant, near Cedar Cove. No
rain fell in either Estes Park or Loveland. By 2:00
a.m. of June 22, the river had reac~flood stage and
continued at that level until 6:00 a.m., when the crest
of the flood had passed through Loveland. FlOoddamage
was primarily to bridges and roads, although the slaughter-
houses east of Loveland were also flooded.

July 19, 1945 - A storm of cloudburst proportions struck
the watershed of Cedar Creek. Two inches of rain fell
in a few minutes causing a wall of water several feet
high to strike the Big Thompson River. Official reports
state that the river had risen from a flow of 462
cubic feet per second on the preceeding day to
5000 to 6000 cubic feet per second when the flood
occurred. Flood waters choked the intakes to the
Loveland Municipal Filter Plant. Road beds and bridges
were heavily damaged by debris and erosion by high-velocity
flood waters.

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