Using an Iridium Satellite Telemetered Gage (iGage) for Hydrologic, Snowfall, and Coastal Storm Surge Measurements to Support Forecast Operations in Alaska

Data sparseness in Alaska poses a challenge for National Weather Service (NWS) meteorologists and hydrologists responsible for the forecasting of hazardous weather and flooding conditions. Reliable real-time hydrometeorlogic data is critical information needed by forecasters when issuing warnings to the public for river or coastal flooding, heavy snow events, and other hazardous weather.

In cooperation with the U.S. Army Corps of Engineers and the State of Alaska, the NWS developed and tested a compact, low cost, ultrasonic iridium satellite telemetered gage (iGage) that is used to measure hourly snow depth, river stage, and coastal water levels. The iGage is battery and solar powered and can quickly be mounted to a static structure over a water or snow surface. The NWS has successfully installed the iGage on highway bridges across Alaska during the summer open-water season and now receives stage data on previously ungaged rivers and streams. The iGage is removed from the bridges in the autumn and deployed elsewhere to provide forecasters with hourly snowfall and snow depth in the winter. In addition, iGages have been mounted on bridges over estuaries in coastal Alaska and provide tidal and storm surge data during the fall Bering Sea storm season. The NWS also tested an iGage from a stationary position on a riverbank that took oblique river stage measurements with the intention of deployment in rural, riverine communities off the road system that lack bridges.

This presentation will discuss how the iGage has improved NWS forecaster situational awareness, decision support services for customers and stakeholders, and verification of hazardous weather events in Alaska.