So far this year, Seattle has seen nearly 6.5 “of rain. With an additional forecast of 2-4 centimeters, the city could receive about 15% of its annual rainfall on January 15 from the atmospheric river that drowns the region.
“This soaked start could push Seattle to its single wettest start of any year on record. The previous wettest period from January 1 to 15 took place in January 1956, when the first half of the month dropped nearly 7 inches,” the CNN says meteorologist Pedram Javaheri.
Atmospheric rivers are long, narrow regions in the atmosphere – such as rivers in the air – transporting water vapor, according to the National Oceanic and Atmospheric Administration.
View the forecast across the countryy
There is also a lot of heat in the middle level of the atmosphere during this particular atmospheric river event. This will increase snow levels at altitudes above 6000 feet over many of the Cascades, with rain falling below the level.
“This will further exacerbate flooding problems as heavy rains fall on top of abundant snow. The threat of rapid melting, increased runoff and downstream river flooding is something that everyone in western Oregon and Washington must watch out for,” Javaheri said.
Higher altitudes in Washington can rain from 2 to 4 inches during the next 24 hours, increasing the risk of flooding and landslides.
Rainfall at lower altitudes should be between 1 and 2 centimeters during the time.
In Portland, Oregon, the National Weather Service forecast until Wednesday morning up to 7 inches of rain in the higher terrain and up to 2 inches for the lowlands. Along with that, there is a warning against strong winds.
Wind warnings span the entire Oregon coastline, where gusts can reach up to 75 km / h. This raises concerns about felled trees, power outages and potential dangers along Interstate 5.
The effects of the wildfires that set the record also lead to the threats to Oregon. According to the Oregon Department of Forestry, more than 1 million acres burned. These remaining scars make the flood threat even greater due to charred soil without vegetation to absorb the rainwater. This increases the possibility of flash floods and landslides due to the loose terrain.
The culprit
The weather phenomenon that causes all this rain is called an atmospheric river. They are basically moist rivers high in the atmosphere. They carry abundant moisture from tropical regions and release it in other areas in the form of rain or snow.
According to NOAA: “These vapor columns move with the weather and carry an amount of water vapor that is approximately equal to the average flow of water at the mouth of the Mississippi River.”
Not all atmospheric rivers are bad. They often carry very beneficial rain to areas that need it. Many areas along the West Coast will receive 30% -50% of their annual rainfall in just a few such occasions.
This particular atmospheric river has a span of 2700 miles with a view of the Northwest. This is equivalent to the distance from Seattle to Miami as the crow flies, and the moisture it carries could possibly place January 2021 in the record books.
Hurricane Hunters Drive to West Coast
This atmospheric river event is so important that hurricane hunters will fly through it and drop buoys.
“To really understand how important an atmospheric river event will be, you have to get to it. Hurricane hunters fly into it and collect valuable data that forecasters use to determine how a particular atmospheric river will affect the Pacific coast,” he said. CNN meteorologist Allison Chinchar.
This is their second flight of the season and something they do regularly.
“The hurricane fighters started flying in atmospheric rivers for the first time in February 2016 and have been sending out 6-12 flights every January since then. In itself, it is not uncommon for them to fly this event, although it is a popular one. misconception that as soon as the hurricane season winds die, their role also applies, ‘says Javaheri.