Isohyetal Maps


Product Overview


Isohyetal maps spatially present extreme precipitation return period amounts (inches) across New York.  These maps are available for various accumulation periods (24-hr, 18-hr, 12-hr, 6-hr, 3-hr, 2-hr, 1-hr) and recurrence intervals (1-yr, 2-yr, 5-yr, 10-yr, 25-yr, 50-yr, 100-yr).  It is estimated that precipitation events equal to or greater than the magnitudes presented on these maps will be separated, on average, by the number of years specified by each recurrence interval.