by Sadie Shields
An atmospheric river brought weeks of heavy rain to Northern California and the Pacific Northwest, dumping record-level precipitation in some areas and pushing rainfall totals above seasonal averages, according to the National Weather Service.
Over 10 inches of rain were reported in Eureka from mid-December to early January, while Honeydew in southern Humboldt County has seen nearly 70 inches of rainfall since mid-October, according to National Weather Service meteorologist Jacob Boomsna.
“An atmospheric river is a narrow band of moisture that usually brings moisture in from the tropics — long-lasting and intense,” Boomsna said. “Usually when we get those, it’s heavy rain and lots of precipitation.”
Unlike hurricanes and typhoons, which are tropical storms that form over warm ocean waters with a defined center of low pressure and rotating winds, atmospheric rivers are long, narrow bands of moisture that transport water vapor from the tropics or subtropics toward higher latitudes. They don’t have wind-speed classifications, though they can still bring strong winds. According to Boomsna, Cape Mendocino on the Lost Coast recorded wind gusts near 100 miles per hour during the recent storm.
The prolonged rainfall led to widespread flooding, especially in low-lying and river-adjacent areas of Humboldt County. Deputy Raleigh Willoughby, lead swiftwater rescue technician for the Humboldt County Sheriff’s Office, worked rescue operations during the December atmospheric river event.
“During this most recent atmospheric river event, the areas that were most affected tended to be low-lying regions, river corridors and locations with poor drainage,” Willoughby said. “Communities near the Eel River, Freshwater Creek, Mad River, Elk River, Jacoby Creek and smaller tributaries experienced flooding, roadway impacts and rapid rises in water levels.”
Rural roads, agricultural areas and locations where creeks cross under roadways were particularly vulnerable. Willoughby added that even areas that don’t usually flood can be impacted during prolonged or intense rainfall.
With floodwaters moving quickly, officials stress that personal safety should always come first.
“The most important advice is to prioritize personal safety and avoid taking risks,” Willoughby said. “If you are in a vehicle, do not attempt to drive through flooded roadways. Moving water is extremely powerful and can easily sweep a vehicle away.”
Willoughby warned that if people become stranded, they should stay with their vehicle if it is safe, move to higher ground if necessary and call 911. Entering moving water on foot is also dangerous.
“It takes very little depth and current to knock a person off their feet,” Willoughby said. “When in doubt, stop, wait and seek help rather than trying to self-rescue. If you cannot clearly see the bottom or determine how deep the water is, it should be treated as dangerous and avoided.”
Warning signs include fast-moving water, muddy or opaque floodwater that may hide debris or washed-out roads and rising levels that cover familiar landmarks. Both local responders and weather officials emphasize preparation and patience during major storm systems.
“Flooding and swift water incidents are some of the most dangerous situations both for the public and for first responders,” Willoughby said. “Many rescues are preventable if people slow down, plan ahead and respect the power of moving water.”
Boomsna noted that while Humboldt County is currently experiencing a short dry period, there’s no cause for concern yet.
“The [previous and recent] precipitation brought us above normal,” Boomsna said. “The little dry spell Humboldt is currently having is not something to worry about. There’s still plenty of time for more rain — hopefully not all at once.”
Sadie is a junior communications major, journalism minor at Cal Poly Humboldt as well as an intern for the Cal Poly Humboldt Athletics Social Media team. She can be reached at sls331@humboldt.edu.