WMOD00277

• Contract/Permit #: 14-06-D-6467
• Title: An Operational Adaptation Program for the Colorado River Basin
• Prepared By: Lewis O. Grant, Chappell, Crow, Mielke Jr., Rasmussen, Shobe, Stockwell, Wykstra
• Date: 10/1/1969
• State: CO
• Country: United States
• Weather Modification - Doc Type: Report

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FREQUENCY OF OCCURRENCE

ERCENTAGE OF TOTAL SNOWFALL

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PRECIPITATON INTENSITY
(INCHES)

Figure 24. --Distribution of snowfall at Climax,
Colorado,as a function of the hourly intensity. Data
is for November through May, 1964-67.

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,I C, Wagon Wheel Gap, 3N

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,04 .08 .12 .16 ,20 .24 .28 ,;2 ,36 ,40
INTENSITY OF PRECIPITATION

Figure 25, --Cumulative distribution of snowfall
intensity at San Juan Mountain stations,
November through April, 1948-1968.

Figure 25) shows that the hourly
precipitation rates are. 02 inch per
hour or less 700/0 of the time, and
.04 inch per hour or less 890/0 of the
time. The cumulative curves of
precipitation fre quency for Telluride
(Curve B, Figure 25), another San
Juan Mountain precipitation station,
and for Wagonwheel Gap (Curve C,
Figure 25), a station to the lee of the
San Juan Mountains are quite similar.

Lower elevation and upwind stations
in the San Juan area exhibit a some-
what greater proportion of higher
precipitation intensities but actual
values are still low. This somewhat
greater proportion of higher hourly
intensities is believed to result from
reduced amounts of precipitation
received from orographic influences
co mp are d with that received
from storm situations having deeper
cloud systems. Even for these
stations, as can be seen for Durango
(Curve A, Figure 26), some 600/0 of
the hourly precipitation still occurs
at intensities of .02 inch or less and
.04 inch per hour or less is experi-
enced 800/0 of the time.

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A, Durango
8, Mesa Verde
C, Ouray

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INTENSITY OF PRECIPITATION

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Figure 26. - -Cumulative distribution of snowfall
intensity at lower elevation stations in the San Juan
area, November through April, 1948-1968.

The few hours of higher intensity
precipitation in the San Juans make
a greater contribution to the total

sample period in this case is the
20-year period, November 1948'
to April 1968. Silverton (Curve A,

41