Juneau, Alaska — A powerful Pacific storm setup is once again putting communities from southeastern Alaska to western Washington on edge, as heavy rain falling on deep snowpack raises the risk of flooding, avalanches, and landslides into early week.
Forecasters say this is not a fast-moving system. Instead, a prolonged surge of moisture will repeatedly soak the region, increasing runoff in areas where the ground and mountainsides are already under stress from weeks of snow and rain.
Atmospheric River Brings Days of Steady Rain
The unfolding situation is being driven by a long-lasting atmospheric river, a narrow but intense stream of moisture transported inland by the jet stream.
According to meteorologists, this setup is capable of producing several days of continuous rainfall, which is far more concerning than short bursts of heavy rain.
The highest totals are expected across coastal British Columbia, where 4 to 8 inches of rain could fall through Tuesday. Areas farther south, including western Washington, will also see rounds of rain, particularly across the Olympic Peninsula and the northern Cascade foothills.
Juneau Faces High-Risk Rain-on-Snow Event
The most dangerous impacts are expected in Juneau, where forecasters say 4 to 6 inches of rain could fall by midweek.
To put that in context, Juneau typically averages around 6 inches of precipitation during the entire month of January. This storm could deliver nearly that amount in just a few days.
What makes the situation especially concerning is the snow already on the ground. From December 1 through January 10, Juneau recorded 94.8 inches of snowfall, nearly four times the historical average for that time frame.
“Heavy rain combined with temperatures climbing into the 40s will cause rapid snowmelt,” forecasters warned.
Melting Snow Adds Fuel to Flood Threat
As warmer air moves into the region, snow levels will remain unusually high, meaning precipitation will fall as rain over much of the terrain that would normally see snow.
This creates a dangerous chain reaction:
- Rain accelerates snowmelt
- Meltwater rapidly increases runoff
- Streams, creeks, and rivers rise quickly
- Steep slopes become unstable
Forecasters say this setup significantly increases the risk of flooding and avalanches, especially along the mountains and hillsides surrounding Juneau’s eastern neighborhoods.
Read Also: Avalanche Near Longs Pass Kills Two Backcountry Tourers, Prompts Rescue Effort in Central Washington
Avalanche and Landslide Concerns Grow
Avalanche experts note that rain falling on an existing snowpack weakens its structure, making it more likely to slide.
With snow levels staying elevated throughout the event, the threat of:
- Avalanches
- Debris flows
- Landslides
will remain elevated, particularly in mountainous and coastal regions of Alaska and British Columbia.
Pacific Northwest Also Monitoring Rising Waterways
Farther south, impacts in Washington are expected to be more localized but still potentially disruptive.
While Seattle may see lighter rainfall, surrounding areas that drain the Olympics and Cascades could experience rapid rises in rivers and streams. Officials say even moderate rainfall could push waterways toward flood stage because soils are already saturated.
Residents in low-lying and flood-prone areas are being urged to stay alert as conditions evolve.
Pattern Shift Brings Relief Later This Week
There is some relief ahead.
Forecasters say the stormy pattern should ease later in the week as high pressure builds from the eastern Pacific into the interior West, cutting off the steady supply of moisture.
“This pattern change should give the West Coast a break from heavy rain, flooding, and landslides,” meteorologists said.
During the calmer stretch, temperatures are expected to run 5 to 10 degrees above average, helping stabilize conditions — though runoff issues may linger even after rainfall tapers off.
Officials Stress Vigilance During Peak Risk
Emergency managers across the region are urging residents to remain cautious, especially those living:
- Near rivers or streams
- Below steep terrain
- In avalanche-prone areas
Officials recommend monitoring forecasts closely, avoiding unnecessary travel in high-risk zones, and being ready to act quickly if conditions worsen.
As this atmospheric river continues to impact the region, forecasters stress that rain-on-snow events are among the most dangerous winter weather setups, and preparedness can make a critical difference.
Are you seeing rising water, melting snow, or hazardous conditions where you live? Share what you’re experiencing and how your area is responding in the comments below.
