A flood watch and warning has been issued to parts of Oregon while the state undergoes heavy rain, categorized as an atmospheric river. The flood watch is in effect through this evening, Wednesday, December 6th. According to the National Weather Service, rainfall is expected to be sporadic through to Wednesday evening, having started heavily coming down on Monday evening. From Thursday to Monday, parts of the state saw about 2.5 inches of rain and from Monday to Wednesday night, meteorologists are expected to receive a total of another 2 to 2.5 inches. This rainstorm comes after a snowstorm, which is now melting. The melted snow is coming from some parts in which there was over 8,000 feet snow levels, which is worsening the concern of flooding, as it comes down with the rain.
Flood watches are issued to all areas west of the Cascades.
Currently, the National Weather Service is expecting flooding in small rivers and creeks as well as roads typically prone to flooding. The Cascades are also expected to see increased water levels with possible flooding in their rivers, most prominently from the melting snow. People have been urged to avoid local rivers, even evacuating depending on the proximity of the river.
Over the weekend, some cities were able to clear snow drains out in anticipation of the increased rainfall and snow melting. Portland is one city who managed to do this, with the Portland Bureau of Transportation going through and clearing the drains. On Monday, this same governing body went through some parts of the area to check for potential landslides in the region, in hopes to create barriers to prevent anything from worsening.
What exactly is this atmospheric river the state is seeing?
An atmospheric river is a weather pattern seen in the Pacific Northwestern region of the United States. It was previously referred to most often as the Pineapple Express, but recently has been dubbed an atmospheric river. It is a narrow, but long region in the atmosphere that can move moist air from tropical climates to higher latitudes. These most often form from the Hawaii regions and travel up the channel, reaching the Pacific Northwest. On it’s journey, water vapor is released, creating heavy rain and snow patterns. It usually then leads to flash floods and mudslides, hence why Oregon is seeing all of these issues as we speak.