Heavy rain and snow in the mountains will fall in the Northwest U.S. this week as two storm systems from the Pacific Ocean are fed by an air river.
These systems of atmospheric rivers bring heavy rain and snow to places that need it from the central Pacific.
As of Monday, moderate to heavy rain and snow at high elevations were falling in much of the Pacific Northwest. The rain and snow were also moving inland and into northern California.
The first storm is expected to last until Tuesday, bringing steady snow and rain to the area.
After that, a second, stronger system will come right after it. It will hit the coast on Tuesday night and last at least until Wednesday, maybe longer.
The National Weather Service (NWS) says this second wave will bring more rain and moisture, which makes them worry about floods in some places and a lot of snow in mountainous areas. Up to 12 inches of snow could fall in the Cascades, making driving dangerous in some high-altitude areas.
NWS scientist Anna Lindeman talked about how the atmospheric river is making these storms worse.
According to Newsweek, this happens when a “good moisture cap” forms in the central Pacific. This lets tropical moisture from far out in the ocean come in.
The NWS says that normal air rivers carry the same amount of water vapor as the normal flow at the mouth of the Mississippi River. Strong systems, on the other hand, can move up to 15 times that much.
When the second storm hits, coastal areas, especially Washington State, will get several inches of rain. The Olympic Peninsula will get between 4 and 6 inches. Even though Oregon may get a little less rain, a lot of it is still expected.
“It looks like they’re going to get a little bit less than that further South in Oregon, but we’re going to get some pretty hefty precipitation,” said Lindeman.
The NWS is keeping a close eye on the Skokomish River in Washington because the heavy rains could cause the water levels to rise there. However, widespread flooding is not expected.
“We’re keeping an eye on how much rainfall we get and where the snow levels are because that will have a big impact on how much rivers rise,” he said.
The NWS tells people in the affected areas to keep an eye on weather reports as the situation changes.
Lindeman told people to be careful on the roads, especially where there is standing water.
“If you see standing water on the roadways, don’t drive through it,” she warned. “You never know how deep it is, and it only takes six inches of water to completely wash away your vehicle.”
Lindeman told drivers going through hilly areas where heavy snow is expected to pay attention to road signs and make sure their cars have chains in case they need them.
