7012

• UCREFRP Catalog Number: 7012
• Author: Cross, J. N.
• Title: Ecological Distribution of the Fishes of the Virgin River ‎(Utah, Arizona, Nevada)‎.
• USFW Year: 1975.
• USFW - Doc Type: University of Nevada,
• Copyright Material: NO

11
CLIMATE
The climate of the Virgin River basin ranges from aril in the
valley floors in the southern part of the basin to humid in the
mountains to the north. Over most of the basin the climate is grid
to semiarid, with little precipitation, mild winters, hot summers
and high evaporation rates.
The climatic pattern of the Virgin River basin is typical of
the Southwest: a biseasonal regime characterized by two periods of
precipitation (winter and summer) and Cara periods of drought (spring
and fall)(Lowe-1964 and references cited therein). The greatest
amount of precipitation occurs from December through March (regional
storms) as snow in the mountains and rain at the lower elevations.
In the summer precipitation is commonly localized thunderstorms which
result in rapid runoff (fl-ash fi~ooding is common) and much erosion
(Cordova et al. 1972, Glancy and Van Denburgh 1959;. In general
the northwesterly grinds of winter and the southwesterly winds of
summer control precipitation while differences in altitude determine
the temperature ". but the influence of these factors is so
~greatiy modified by topography that each deep canyon, wide valley,
broad slope, and plateau top seems to have a climate of its own"
(Gregory 1950, p. 28). -
~ .. ..
Mean monthly and annual temperatures for selected stations are
presented in Table ]. Mean monthly and annual precipitation records
for selected stations are presented in. Table 2. The average annual
precipitation over the entire basin is approximately 30 cm and