Alaska High-Water Mark Observations

High-water marks (HWMs) are critical indicators left by floods—such as mud lines, debris, or seed lines—that show the peak elevation reached. They are essential for mapping flood inundation, improving hydraulic models, informing future infrastructure design, setting insurance rates, and increasing community awareness of flood risk

Collecting high-water marks helps communities document flooding to assist with emergency management and future planning. Building a reliable record of high-water marks also helps improve the accuracy of flood models and predictions.

The Alaska Division of Geological & Geophysical Surveys (DGGS) has developed a tool for community members to submit high-water mark observations and help improve flood forecasting, planning, and safety throughout Alaska.  It is critical to capture high water marks just after a flood.  Use the QR code below to help your community! 

How to collect High-Water marks:  Alaska High-Water Mark Observations Guide

Observation tool link or use the QR code below