Heavy precipitation associated with a large storm system resulted in major flooding in several areas of south-central Alaska during October 10-12, 1986. Flooding was particularly severe in the Seward area of the Kenai Peninsula and in tributaries to Susitna River from Telkeetna downstream. Flood damage has been estimated at $20 million and the region was declared a Federal disaster area. The report includes a brief discussion of meteorological conditions that caused the unusual amounts of precipitation, a summary of flood stages and discharges, a comparison to prior floods, flood-frequency estimates, a brief description of flood areas, and hydrologic data for each area.