So far this year, Seattle has seen nearly 6.5 “of rain. With an additional 2-4 inch forecast, the city could receive about 25% of its annual rainfall by Jan. 15 from the atmospheric river that soaks the region.
“This soft start could drive Seattle to its only wettest start in any year recorded. The previous wettest period from January 1 to January 1 occurred in January 1956, when nearly 7 inches fell in the first half of the month,” says CNN meteorologist Pedram Javaheri.
Atmospheric rivers are long, narrow areas of the atmosphere – like rivers in the sky – that carry water vapor, according to the National Oceanic and Atmospheric Administration.
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There is also plenty of warmth in the middle of the atmosphere during this particular atmospheric river event. This raises the snow level to heights above 6,000 feet above large parts of the cascades, with rain falling below this level.
“This will further exacerbate flooding problems as heavy rain falls 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 should be aware of,” Javaheri said.
Higher altitudes in Washington could see 2 to 4 inches of rain over the next 24 hours, increasing the risk of flooding and landslides.
Precipitation at lower altitudes should be between 1 and 2 inches during this time.
In Portland, Oregon, the National Weather Service Office has predicted up to 7 inches of rain in the higher terrain and up to 2 inches for the lowlands through Wednesday morning. Along with that, there is a warning of strong winds.
Wind warnings stretch along the entire Oregon coast, where gusts can reach up to 75 mph. This raises concerns about fallen trees, power outages and possible hazards along Interstate 5.
The effects of the record-breaking forest fires are also increasing the threat of flooding for Oregon. According to the Oregon Department of Forestry, more than 1 million acres burned. These burning scars that remain make the flood threat even greater due to charred soil with no vegetation to soak up the rainwater. This improves the possibility of flooding and landslides due to the loose terrain.
The weather phenomenon that causes all this rain is called an atmospheric river. They are basically rivers with moisture high in the atmosphere. They carry abundant moisture from tropical areas and release it in other areas in the form of rain or snow.
According to NOAA: “These steam columns move with the air and carry an amount of water vapor that is roughly equal to the average flow of water at the mouth of the Mississippi River.”
Not all atmospheric rivers are bad. Many times they carry very beneficial rain to areas that need it. Many areas along the west coast receive 30% -50% of their annual rainfall in just a few such events.
This particular atmospheric river has a span of 2,700 miles with a bullfight to the northwest. That equates to the distance from Seattle to Miami when the crow flies, and the moisture it carries could possibly place January 2021 in the record books.
Hurricane hunters find their way to the west coast
This atmospheric river event is so marked that hurricane hunters will fly through it and release buoys.
“To really understand how important an atmospheric river event will be, you have to get close to it. Hurricane hunters fly inside them and collect valuable data, which forecasts then use to determine how a particular atmospheric river will affect the Pacific Ocean. coastal region, “said CNN meteorologist Allison Chinchar.
This is their second seasonal flight, and something they do regularly.
“Hurricane fighters began flying in atmospheric rivers for the first time in February 2016 and have been sending 6-12 flights every January to March ever since. In itself, it is not uncommon for them to fly this event, although it is a popular misconception about , that when the hurricane season wind dies, so does their role, “says Javaheri.