Ice dams aren’t as constant a threat here as they are in snowier climates, which is exactly why Vancouver and Portland-metro homeowners are often caught off guard by them. Most winters bring a cold snap or two with enough snow accumulation and freeze-thaw cycling to form one, and because it doesn’t happen every year, a lot of homes have attic insulation and ventilation that was never really tested against it — until the year it is.
Here’s what’s actually happening on your roof when an ice dam forms, and what to do if you find water coming in around the eaves during a winter storm.
What an ice dam actually is
An ice dam forms when heat escaping from inside the attic warms the upper part of the roof enough to melt the snow sitting on it, even while outside air temperature stays below freezing. That meltwater runs down the roof deck until it reaches the eaves — the unheated overhang past the exterior wall line — where it refreezes because that section of roof isn’t getting the same attic heat leaking up into it. Over a sustained cold snap, that refreezing builds a ridge of ice right at the edge of the roof.
The ridge itself isn’t the problem. The problem is what happens behind it: more meltwater keeps running down from higher on the roof, hits the ice ridge, and has nowhere to go but backward — up and under the shingles, which are designed to shed water running downhill, not water pooling and pushing uphill against them. That water finds its way through the roof deck and into the attic insulation, the ceiling below, or down inside exterior walls.
Why it happens more in some homes than others
The dominant factor is attic heat loss, not how much snow falls. A well-insulated, well-ventilated attic stays close to outside air temperature, so snow on the roof melts slowly and evenly and doesn’t refreeze into a dam at the eaves. An attic that’s leaking warm air — from gaps around recessed lighting, an attic hatch without a seal, insulation that’s thin or compressed, or a bathroom fan vented into the attic instead of outside — melts snow unevenly, which is exactly the setup that produces an ice dam.
Older homes in Vancouver and Portland’s close-in neighborhoods, with attic insulation that predates current energy codes, are more prone to this than newer construction with modern insulation and soffit-to-ridge ventilation. Homes with complex rooflines — dormers, valleys, multiple roof planes — also collect more ice at the transitions where meltwater concentrates.
What to do if you spot one forming
Don’t get on the roof. A roof with snow and ice on it is dangerous footing, and a ladder against an icy gutter is its own hazard. Ice dam removal by chipping or hacking at the ice also commonly damages shingles in the process, turning a water problem into a roofing problem.
Watch for water inside, not just ice outside. The ice dam itself isn’t the emergency — water finding its way past it and into the house is. Check ceilings near exterior walls, especially under valleys or dormers, for new staining, and check attic insulation near the eaves for dampness if you can safely access the attic hatch.
A long-handled roof rake, used from the ground, can reduce new snow load on the lower few feet of roof before it has a chance to melt and refreeze, but this only helps if it’s safe to do from ground level and the snow is still loose — it won’t remove an ice dam that’s already formed.
If water is actively coming through, treat it like any other roof leak: a bucket or tarp inside to catch what’s coming through, away from anything electrical, and a call to a restoration contractor. This is the same first-response logic we cover in more depth in our guide to what to do when a tree falls on your house — stabilize what you safely can, then get help moving on the rest.
What happens once a crew is on-site
Ice dam damage gets handled with the same discipline as any other storm damage restoration call, with a sequence built around the fact that the visible ceiling stain is rarely the whole story:
- Safe ice and snow removal from the roof, done by a crew equipped for it — not a DIY ladder job.
- Emergency tarping or roof protection if the ice dam has already compromised shingles or roof deck, using the same approach detailed on our emergency roof tarp page.
- Interior assessment with moisture meters to find where water traveled inside the attic, ceiling, and wall cavities — ice-dam water frequently spreads well past the point where it entered.
- Structural drying, following the same water damage restoration protocols used for any interior water intrusion, so wet insulation and framing don’t turn into a mold problem weeks later.
- Roof repair and interior rebuild — replacing damaged shingles, roof deck, insulation, drywall, and paint, matched to existing finishes.
Insurance and ice dams
Ice and snow load damage is generally covered on standard homeowner policies as a named peril, and the resulting water damage from an ice dam is typically treated the same way — as sudden damage from a covered cause, not a maintenance issue. We go into more detail on how storm-related claims are evaluated, including where carriers draw the line between a covered event and pre-existing deferred maintenance, in our guide to whether homeowners insurance covers storm damage. As with any claim, documenting the damage before repairs start matters, and we photograph and measure before any tarping or demolition begins.
The long-term fix
Once the immediate water intrusion is handled, the actual prevention work happens in the attic, not on the roof: better insulation at the ceiling plane, sealing the air leaks that let heat escape upward, and confirming soffit-to-ridge ventilation is actually working. A roof that keeps forming ice dams every cold snap usually has an attic problem, not a roofing problem — and fixing the attic is what stops the next storm from causing the same damage again.
If you’ve got water coming through your ceiling during a winter storm, call TIK Construction at (360) 938-4601. A real person answers 24/7, and we handle the roof, the interior drying, and the rebuild as one job.