Sixteen Year Study of Minnesota Flash Floods

This study provides climatological data and facts on 16 years of flash floods in Minnesota that occurred from 1970 through 1985. The information is based on 5 7 flash floods and includes data on their areal extent, maximum rainfall amounts. orientation, time of occurrence. probability of occurrence, and precipitation network history. The definition of a flash flood as used here is the occurrence of 6-inches or more rainfall within a 24-hour period. The size of a flash flood is the measured area in square miles over which a 4-inch or more rainfall occurs. The rationale for using these two criteria is that a rainfall of six inches in a 24-hour period is near the 100-year return period in Minnesota and, second. a 4-inch and greater rainfall approximates the level at which newspaper reports indicate increased erosion or other economic damages are associated.