New Satellite Based Flash Flood Alerting System for Grand Canyon, Arizona

Each year, over 24,000 people embark on guided river trips along the Colorado River in the Grand Canyon. The Colorado River in Grand Canyon National Park stretches across 277 miles of remote, backcountry wilderness with boating/rafting trips lasting from a few days to as long as 25 days. The majority of these trips occur during the summer months, coinciding with the North American Monsoon (NAM), which brings the threat of torrential rains and life-threatening flash floods. There is little to no cell phone coverage in Grand Canyon or along the Colorado River, and there are long stretches of the river with non-existent NOAA weather radio coverage. Therefore, the traditional methods for communicating weather hazards and warnings do not work throughout much of the Grand Canyon. Satellite messaging devices have proven to be effective and routinely used by recreationalists for communication.

In a joint effort between the U.S. Geological Survey Grand Canyon Monitoring and Research Center (USGS-GCMRC), Coconino County Emergency Management (CCEM), the National Weather Service (NWS) Flagstaff, and the Grand Canyon National Park Service (NPS), a new alerting system was developed and implemented for sending emergency alerts to satellite devices along the Colorado River and throughout the backcountry of Grand Canyon. The goal of the project is to enhance safety for boaters and hikers navigating rugged and remote areas of Grand Canyon.

CCEM, through the use of RAVE Mobile Safety, has the capability to send text message notifications to satellite messaging devices (such as GARMIN In-Reach or SPOT). Most river guides travel with these devices for emergency communications. Once a Flash Flood Warning is issued along the Colorado River, CCEM sends a shortened satellite-based text message through RAVE to alert recreationalists of the flash flood hazard. USGS has provided NWS Flagstaff with updated geo-referenced datasets such as river miles and well known campsites to use in our flash flood warnings to improve their effectiveness to boaters and hikers. The NWS and USGS are working together to develop a community science application for reporting flash flood events which will improve the verification and documentation of flash floods and debris flows within the Grand Canyon.

Summer 2024 is the pilot season of this project, and as of August 13, 2024, there are already 696 parties subscribed to receive these alerts for Grand Canyon. This project helped establish inter-agency communication paths between the National Park Service, U.S. Bureau of Reclamation, and Coconino County Emergency Management to send alerts containing search and rescue information, boating hazards, and dam-related events. NWS Flagstaff will be reviewing the use of sending additional weather-related alerts (heat, flash flood watches, severe thunderstorm warnings) for future seasons. This AMS presentation will elaborate on the inspiration behind this project and the collaborative process we underwent with key partners to implement it. This first of its kind alerting system could have far-reaching implications across the agency for other NWS offices that serve remote recreational areas.