NOAA Atlas 2, Volume 9, Precipitation
Frequency Atlas of the Western United States, (1973).
Generalized maps are presented for 6- and 24-hr point precipitation
for the return periods of 2, 5, 10, 25, 50, and 100 years.
Equations and interpolation diagrams are provided for determining
values for durations less than 24 hours and for intermediate
return periods. Area reduction curves for adjusting point
values for areas up to 400 square miles are included. This
Atlas is published is published in separate volumes for each
of the States.