The Northwest is no stranger to wet weather, but when meteorologists are referring to an "atmospheric river" causing the rain, what does that really mean? AccuWeather's Anna Azallion explains.
00:00Well, it's that time of year that we are talking about storm after storm, a parade of storms into, especially the northwest.
00:08And sometimes we get a storm that we call an atmospheric river.
00:12We've already had one in the last month at least.
00:15So if you're wondering, okay, what exactly is this?
00:17What's the difference between just the normal storms we're talking about right now versus an atmospheric river?
00:22Let's break it down.
00:23So it all has to do with the moisture, where it's coming from, and how it ends up getting to the northwest.
00:30So the setup is always the same.
00:32We have winds that are moving over the waters of the Pacific Ocean, and they're funneling moisture to the northwest.
00:39You can think of it like a funnel, but if you have different sizes of a funnel, because we can get wind over a very large, widespread area as far as that moisture.
00:50Or if it becomes more concentrated, that's when we start to get towards our atmospheric river.
00:55It's called an atmospheric river because you can really think of it like a river.
00:59It's into a narrow band, and all of that moisture gets funneled in just like water moving through a river.
01:06Now, the strength of this atmospheric river, it depends on the wind speed and the location.
01:12So that's why sometimes an atmospheric river event drops more rain than maybe the last one that you experienced.
01:19Now, let's talk a little bit about the impacts, because that's where the importance of is it an atmospheric river or is it not.
01:25That's where this really comes in.
01:27Oftentimes, we get upwards of even a foot of rainfall with an atmospheric river event, which can certainly lead to flooding.
01:33But then especially, we get towards our mountain areas, and then something called orographic lift comes in.
01:39It essentially just means we end up with even heavier rainfall, or if it's cold enough, even heavier snowfall.
01:45You also have to think about burn scar areas.
01:47These are the same parts of the area world that we get wildfires and can lead to more flooding.
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