Pineapple Xpress leads to flooding in Pacific Northwest

Water rescues have taken place in Washington and Oregon as heavy bands of rainfall the last several days have piled on in the Pacific Northwest. Two people have died as a result of this flooding caused by an atmospheric occurrence known as a Pineapple Express.

This occurrence happens when a long narrow band of water vapor is transported from the equator to the north back over land. It can be seen in the relative humidity maps in the lower level jet stream.

As the narrow and saturated band reaches land, the moisture then cools and condenses leading to high amounts of rainfall resulting in the current flooding conditions seen.

Pineapple Express events can lead up to 50% of the measurable rainfall seen in the West coast each year. These atmospheric river events (Pineapple Express events) transport the greatest amounts of fresh water in the world mirror that of a body of water such as the Mississippi river. This event looks to continue into Friday morning before the moisture transport cuts off and conditions dry.