DENVER (KDVR) — Colorado will welcome a weather pattern called the “atmospheric river.”

The powerful and prolonged atmospheric river pattern is setting up for the western region of the U.S. through Jan. 4.

An atmospheric river is a conveyor belt of moisture from the Pacific Ocean. Technically, an atmospheric river, or AR, is a channel of water vapor that gets picked up near Hawaii, then transported by atmospheric wind like the jet stream directly into the West. 

You might’ve heard the phrase, “Pineapple Express,” the other term for an AR. ARs can range from weak intensity to extreme intensity. 

  • An atmospheric river is also known as the "Pineapple Express."

An atmospheric river is like a firehose of moisture. The moisture hits the mountain ranges of the West and is lifted higher into the atmosphere where it develops into heavy rain/snow. Parts of the Sierra Nevada mountain range receive 30-50% of their annual precipitation from ARs.  

Colorado’s landscape can benefit from ARs. With the right intensity and jet stream flow, the mountains can squeeze out heavy snow accumulation. For example, some of the biggest snow events in Crested Butte history are the result of atmospheric river patterns.