04 Nov 2022 | 12:23 PM UTC
US: Adverse winter weather forecast over western regions through at least Nov. 7
Adverse winter weather forecast across parts of the western US through at least Nov. 7. Hazardous travel conditions likely.
Event
An atmospheric river funneling moisture into the northwest is forecast to bring heavy mountain snow, rainfall, and strong winds across large parts of the western US through at least Nov. 7. Widespread rainfall is expected at lower elevations of the northwest and mixed precipitation and snow are likely in mid-to-high elevations. Heavy snow is expected over mountain ranges from the Washington Cascades southeast to the Tetons in Wyoming, with daily snowfall accumulations of at least 20 cm (8 inches) possible. Snowfall is expected in lower elevated areas close to the Canadian border from Nov. 6. The heavy snow accompanied by strong winds will likely lead to hazardous driving conditions due to icy roads and reduced visibility.
Government Advisories
As of early Nov. 4, the National Weather Service (NWS) has issued winter storm warnings over parts of northern Washington, eastern Oregon. northern, central, and southeastern Idaho, western and southern Montana, and western and northwestern Wyoming. Winter storm watches have been issued for parts of eastern California. Winter weather advisories for parts of eastern and northwestern Washington, northwestern and southern Oregon, northern, central, and southeastern Idaho, western Montana, western and southern Wyoming, northern Utah. western and northern Colorado, northeastern and eastern Arizona, and northern New Mexico. Freeze and hard freeze warnings have been issued for parts of western Oregon, central California, southwestern Utah, western and central Arizona, and southeastern New Mexico, as well as frost advisories for parts of central California. Flood and flash flood watches have been issued for parts of northwestern Washington and high wind warnings, watches, and advisories, as well as special weather statements, have also been issued across parts of the affected area. Officials could update and possibly extend the coverage of weather alerts over the coming days.
Hazardous Conditions
Snow accumulations are likely across the affected area. Lesser accumulations are possible where sleet and freezing rain mix with the snow, and precipitation are less intense. In addition to the heavy snow, strong wind gusts will likely lead to periods of blowing and drifting snow in some areas. Blizzard conditions are possible. Sporadic power outages could occur throughout 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 located downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.
Transport
The winter weather will likely cause ground and air transport disruptions over the coming days. Traffic and commercial trucking delays are possible along regional highways. Dangerous and challenging driving conditions are also likely on secondary and rural roads in the affected states as maintenance crews prioritize clearing major routes. Authorities could close stretches of highways if driving conditions become too hazardous. Flight delays and cancellations are likely due to ground stops and deicing operations at regional airports.
In areas where precipitation mainly falls as rain, 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.
Advice
Monitor local media for updated weather information. Verify road conditions before driving in areas where heavy snowfall or rainfall is forecast. Allow extra time to reach destinations in these areas and carry an emergency kit and warm clothes if driving is necessary, especially on secondary or rural routes that could become impassable. If routing shipments by truck through the affected area, plan accordingly for delivery delays. Confirm flights. Charge battery-powered devices in the case of prolonged electricity outages.
