FLOOD00419

• County: Jefferson
• County: Park
• Community: Buffalo Creek
• Title: The Buffalo Creek Flash Flood of July 12, 1996 Draft - A Reconstruction of Rainfall and Meteorology
• Date: 7/12/1996
• Prepared For: CWCB
• Prepared By: Henz Meteorological Services
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

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1,0 Introduction

The town of Buffalo Creek, Colorado was struck by a deadly flash flood
about 900PM on the night of July 12, 1996. The flash flood killed two residents
and produced several hundred thousand dollars of damage to the town. The
cruel irony of the flash flood is that it followed a massive forest fire which burned
12,000 acres of nearby forest land during May 1996. The combined hardships
associated with both of these disasters and the continuing threat of additional
flash flooding has produced serious concerns for the remaining residents of
Buffalo Creek.

The town of Buffalo Creek is located in southern foothills of Jefferson
County about 35 miles southwest of downtown Denver (see Figure 1), The
elevation of the town of Buffalo Creek is about 6,700 feet but it is flanked by
10,421 ft Green Mountain to the south, 11,588 ft Buffalo Peak to the west-
southwest and 11,970 ft Windy Peak to the west (See Figure 2). The average
elevation of the watershed is about 8,500 feet. The Buffalo Creek basin extends
roughly 15 miles to the southwest from the town of Buffalo Creek and varies from
2 to 5 miles wide, The basin covers about 47 square miles of drainage area, It
is easy to imagine that orographic influences on precipitation exist in the basin,

Henz (1974) identified fourteen areas along the Colorado Front Range
which he referred to as orogenic thunderstorm "hot spots" or preferred
orographic locations for thunderstorm generation. He observed that over 2,5
times as many thunderstorms formed over these "hot spots" as the neighboring
terrain at elevations above 5,000 feet during the radar survey periods of the
summers of 1970 and 1971. He identified the orographic characteristics of these
hot spots were very similar and supportive of an enhanced mountain-valley
breeze circulation which appeared to be related to the observed increase in
storm formation over these areas. He recently observed (Henz, 1996) that most
of the significant flash floods which have occurred since 1976 along the
Colorado Front Range at elevations above 6,000 feet have occurred in one of
these "hot spots". The Buffalo Creek watershed is located within the southern
half of his Conifer "hot spot".

Many have suggested that the burn areas of the basin produced a
significant increase to the runoff from the rains of July 12th which ex
acerbated the flash flood. Others have suggested that the burn area has
been responsible for thunderstorm intensification and formation over the Buffalo
Creek basin. This report will not address those concerns directly. Rather, it will
present a coherent presentation of the timing, aerial coverage and intensity of
the rainfall which produced the Buffalo Creek flash flood. Discussions on the use
of radar data and standard surface and upper air observations to produce
precipitation mapping will be presented,

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