Flooding from prolonged atmospheric river expected in Monroe, Snohomish
Published 2:45 pm Friday, March 20, 2026
SNOHOMISH — Flooding along the Snohomish River could inundate roads and farm land near Monroe through the weekend, the National Weather Service said in a Friday warning.
In the flood warning, the National Weather Service in Seattle said that the Snohomish River was expected to rise to 17 feet by noon Friday in the Monroe area. It is expected to crest near 18.3 feet by Friday night. Flood stage along the river in that area is at 15 feet. The flooding will likely impact farmlands, roads and some residential areas, according to the National Oceanic and Atmospheric Administration, known as NOAA. Levees will likely be damaged.
On Friday afternoon, water levels along the Snohomish River were high, forcing the closure of the riverfront trail in Snohomish. That city is also expected to see major flooding around 11 p.m. Friday, with an expected crest of 30.5 feet, according to data from NOAA. Low farmlands and some roads could be flooded, according to NOAA.
Other parts of the county faced less severe flood warnings. The Skykomish River near Gold Bar will see moderate flooding through early Saturday morning, according to the National Weather Service. The Stillaguamish River at Arlington will see minor flooding.
On Thursday, Snohomish Fire District crews rescued a man who had driven past closed road signs into floodwaters, according to a media release Thursday. Nobody was injured.
On Friday, the Snohomish County Public Utilities District announced that water levels in its Spada Lake Reservoir, northeast of Sultan, were expected to reach the top of Culmback Dam’s spillway that afternoon. Water traveling through the spillway — a built-in safety measure at the dam, which allows water to flow out when it reaches a certain height to protect the dam — will be discharged and flow 16 miles to join the Skykomish River near Sultan.
That may lead to localized flooding near the Sultan River, predominantly in low-lying areas, though it is largely dependent on Skykomish River levels, the Public Utilities District, or PUD, wrote in a Friday press release. The PUD has staff on site monitoring the dam and is working in coordination with officials in Sultan.
“The dam and reservoir are safe and secure, and the spillway is functioning as intended,” wrote Scott Spahr, manager of Generation Operations & Engineering at the PUD, in the Friday press release. “This demonstrates the effectiveness of the safety features incorporated into the dam.”
The spill is expected to begin Friday and extend through the weekend, possibly until Monday.
Generally, most rivers undergoing flooding currently will begin to see water levels fall below flood stage by Sunday morning, said Maddie Kristell, a meteorologist at the National Weather Service. Some areas will see sharper declines than others.
The flooding was caused largely by a prolonged atmospheric river, which dropped rain across the Cascade mountains over the past week, Kristell said in an interview Friday.
“Because of the snow that had fallen prior to that, the rain fell on top of the snow, there was a lot of melt there that increased river flows,” Kristell said.
In December 2025, record-breaking floods forced hundreds of evacuations across Snohomish County. One person was killed after driving into floodwaters.
Will Geschke: 425-339-3443; william.geschke@heraldnet.com; X: @willgeschke.
