An atmospheric river is a plume of moisture that comes in from the Pacific Ocean, bringing moisture and rain to the west coast. Less rain is expected in California, but winds accompanying the storm system could be brutal for the firefighters battling some of the countries largest wildfires.
The Weather Prediction Center (WPC) is forecasting as much as 7 inches of rain across several high elevation locations in the Pacific Northwest during the next seven days.
“While early season ARs (atmospheric rivers) tend to produce less precipitation than their mid-winter counterparts, any precipitation that these two ARs produce will bring much needed relief to the numerous active wildfires and drought conditions in the Pacific Northwest,” said the Center for Western weather and water extremes.
Let’s hope this is the case for the more than 600-thousand acres currently burning in active fires between the two states.
The chances of rain dramatically increase for Friday and Saturday. Seattle is expecting as much as two to four inches of rain in the mountains, and an inch or two for the lower elevations.
The same is true for areas farther south. Across Oregon, several inches of rain could fall, with higher amounts in the higher elevations.
Relief for California?
The bulk of the rain won’t have as much of an impact farther south. California is in the midst of one of its worst wildfire seasons in modern history, with more than 7-thousand fires this year that have burned nearly 2-million acres.
Chief Jesse Alexander is with the Yuba City Fire Department and has been fighting the Dixie Fire in northern California
, among other fires, and says he doesn’t believe the small amount of rain they will receive will make much of an impact on what they are dealing with.
“It will take substantial rain to make a real difference.” He also worries that the shift in wind direction with the approaching atmospheric river could actually make fires worse.
“The gusty winds could enhance wildfire activity and there could also be more lightning without much rain,” said Alexander.
“The rain may help on some of the fires by raising the relative humidity levels and providing a little moisture, but five days later, we will be in the same situation.”
Wind gusts of 50 mph are also forecast for much of the region.
The erratic change in winds could make it dangerous for firefighters on the front lines.
However, with fire season, many will take the good with the bad. A little relief with the rain and higher humidity levels could help make a few strides with some of the fires — at least for the short term.
“McCash and Monument fires will hopefully benefit from this weekend’s precipitation,” said The National Weather Service (NWS) office in Eureka, California.
“Rain will bring cloudy weather for the interior, but may help clear out stubborn valley smoke.”
La Nina could bring more rain in the future
La Nina is forecast to return in the next few months, meaning the possibility for more atmospheric rivers like these in the fall
If that’s the case, it could help the wildfire situation, as well as the extreme drought for parts of the west.
Atmospheric rivers account for as much as 30-50% of the annual rainfall for the west.
While they are incredibly beneficial, they can also cause flash flooding events, as well as mudflows on areas scared by wildfires.