16 Mar 2023 | 04:10 AM UTC
US: Flooding ongoing across Arizona, Nevada, and Utah as of late March 15
Flooding and evacuations ongoing across Arizona, Nevada, and Utah, US as of late March 15. Further severe weather forecast.
Event
Flooding and evacuations are ongoing across Arizona, Nevada, and Utah as of late March 15. Authorities have confirmed two fatalities near the Utah-Arizona border due to flooding in a slot canyon. Evacuation orders are in place for parts of Sedona, Arizona, near Oak Creek due to rising river levels. Authorities in Arizona have advised all residents in the area of the Highway 91 bridge in Beaver Dam to prepare to evacuate.
Government Advisories
Further heavy rainfall is forecast. As of late March 15, the National Weather Service (NWS) has issued winter storm warnings for parts of southwestern Utah. Flood watches and warnings are in effect for northwestern and central Arizona, southern Nevada, and far southwestern Utah, while flash flood warnings are in place for far west central Arizona and far southern Nevada.
The NWS's Weather Prediction Center has warned of a slight risk (level 2 on a four-tier scale) of excessive rainfall across parts of western Arizona and far southern Nevada through early March 16. Officials could update and possibly extend the coverage of weather alerts over the coming days.
Hazardous Conditions
The storms could produce rounds of heavy precipitation (including rain and snow), strong winds, and isolated thunderstorm activity in the affected area. Where precipitation falls as rain, flash and areal flooding is possible. Such flooding is possible in low-lying communities near watercourses and other large bodies of water, as well as in urban areas with easily overwhelmed stormwater drainage systems. Sites downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.
Precipitation could fall as snow in the higher elevations over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in mountainous areas. Rain-induced landslides cannot be discounted in areas of elevated terrain; there is also the possibility of avalanches in mountainous areas where the snowpack has become unstable due to heavy snowfall. Power outages are likely throughout the affected area.
Transport
Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected area. Flooding in urban areas could also result in significant traffic congestion. Heavy snow will likely make driving hazardous in some areas; authorities could implement temporary road closures or detours in such locations. Mountain passes and tunnels could be closed as a precautionary measure during periods of intense snowfall.
The disruptive weather will likely cause some delays and cancellations at airports in the region. Authorities may temporarily suspend port operations along the Pacific coast if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding or snow could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track blockages.
Disruptions triggered by inclement weather and resultant hazards, such as flooding or avalanches, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.
Advice
Monitor local media for weather-related updates and advisories. Confirm all transport reservations and business arrangements before traveling in the affected area. Seek updated information on road conditions before driving or routing shipments through areas where severe weather is forecast; plan for possible supply chain disruptions throughout the affected areas. Stay away from elevated streams, creeks, and other watercourses that are prone to flash flooding. Do not attempt to navigate flooded roadways. Exercise caution in elevated terrain due to the threat of landslides, as well as mountainous regions where avalanches pose a threat. Charge battery-powered devices in the case of prolonged electricity outages.
