Atmospheric type 4 rivers can cause flooding in the Pacific Northwest

(CNN) – An atmospheric river Category 4 out of 5 The beginning of the week will bring heavy rains, swollen rivers and snow to the Pacific Northwest.

At the atmospheric level of the river, a type 4 is classified as “mostly dangerous” but “beneficial” based on the amount of rainfall expected. Center for Western Waters and Weather Extreme (CW3E).

Atmospheric rivers are good and bad. On the good side, they are the largest contributors to the West Coast water supply; However, they are also the source of the most shocking flooding in the region.

This week is no exception in terms of heavy rain and flooding in Washington and Oregon.

“Beginning Sunday night, strong atmospheric currents are spreading across western Washington and northwestern Oregon.” Said Office of the National Weather Service (NWS) in Portland, Oregon.

Heavy rain is expected Monday through Tuesday morning, with a total of 3 to 6 inches of 24-hour rainfall over the beaches of Washington and Oregon. During the same period, heavy rainfall is expected in some parts of the Cascade Range.

This heavy rain event comes from a relatively dry start in February. As of Sunday morning, Seattle-Tacoma Airport had received more than 1 inch of rain this month, a deficit of more than 25 inches for February.

While the mountains first experience snow, temperatures rise slowly at higher altitudes, which can lead to a change in rainfall. When this change occurs, rainfall will cause additional snowmelt, which could lead to flash floods and rising rivers in the coming days.

“Rivers in the area are forecast to rise and flood due to heavy rainfall and increased snowfall.” Said NWS office in Seattle. “The current forecast says that most of the rivers in the region are likely to overflow [la cordillera de] With moderate flooding in the Skokomish, Snoqualmy, Nisquali and Koulitz rivers, the layers reach a slight flood level from Monday night to Tuesday. “

As the system moves toward the beach, it winds up Coastal communities and beaches, winds of 64 to 89 km / h are forecast.

At the beach, Sunday sleeper waves are possible, meaning the waves will travel farther than normal on the beach, including rocks and jetties.

“Sleeper waves can suddenly hit people and drag them quickly into the sea, leading to serious injury or drowning.” Said NWS office in Portland.

Extreme levels of flood danger were announced in at least three places on Monday and Tuesday.

By Tuesday night, a little break from heavy rain can be seen in the northwestern Pacific before another round of rain on Wednesday.