A huge humid atmospheric river has caused severe flooding in the northwestern United States over the past few days, causing a series of areas to be deeply flooded, highways to be paralyzed and people to be evacuated.
The National Weather Service (NWS) said heavy rain will gradually decrease from this afternoon, but the extreme weather is not over yet.
A huge amount of moisture has been washed up on the Pacific coast since December 9, releasing 130-250mm of heavy rain, causing severe flooding in Washington state. Governor Bob Ferguson declared a state of emergency and mobilized the National Guard to support the rescue. Officials have warned that 100,000 people could be evacuated.
In Oregon, floodwaters have begun to recede in some areas, but people have only entered the damage counting stage.
In Canada, heavy rains in the first 24 hours caused the Fraser Valley ( British Columbia) to declare a local emergency, many roads had to be closed.
The NWS warned: The rain will continue until December 12 and continue to worsen flooding on major rivers. There is still a high risk of landslides in many areas west of Washington and northwest of Oregon.
More worryingly, the weather system has not dissipated but is spreading, preparing to interact with two winter storms forming in the eastern United States.
Two winter storms (clippers) are moving rapidly from Alberta ( Canada) - heading towards the midwest and east coast of the US. Typically, they only cause light snow, but this time, the amount of moisture the atmospheric river carries up to the atmosphere will fuel these two storms.
Some areas from the midwest to northeastern United States could see up to 45cm of snow. From Montana to Vermont and further down to Virginia, many have issued winter hurricane warnings.
The first storm is moving eastward, while the second is closely following behind, bringing snow from the Northern High Plains to Ohio Valley and then to Appalachia on December 12. This weekend, New York, Boston and Philadelphia could see the first big snow of the winter.
The core of the current atmosphere will move to British Columbia on December 12, giving Washington an easy breathing by December 12, according to Washington Post weather forecaster Ben Noll. But only from Sunday (December 14), a new atmospheric river will appear and hit the area again.
He wrote on X: The current atmospheric river will combine with a new one early next week and return to attack the northwest Pacific.
In Vietnam, the National Center for Hydro-Meteorological Forecasting said that on December 13, cold air will affect the Northeast and then spread to the North Central, Northwest and Central Central regions.
The weather in the North will turn cold; mountainous and midland areas will be very cold, high mountainous areas will have severe cold. The Northern Delta has some places with severe cold.
Temperature in the mountainous and midland areas of the North is 7-10 degrees Celsius, in high mountainous areas it is below 5°C. Northern Delta: 11-14 degrees Celsius. North Central region: 12-15 degrees Celsius.
Hanoi area: On the night of December 12 and 13, there will be moderate rain, heavy rain and thunderstorms; with the risk of tornadoes, lightning, hail, strong gusts of wind. From December 13, the weather will turn cold, some places will be very cold. The lowest temperature is 12-14 degrees Celsius.
