2026 Jefferson County snow load & ice dam guide
Snow Load and Ice Dams: What 116 Inches a Year Does to a Roof
Watertown averages 116.4 inches of snow a year. That's not a headline number — it's a mechanism, repeated all winter, at the coldest, weakest part of every roof.
Check My Roof PriceThis is a mechanics-and-consequences guide, not an ice-dam removal service. It covers how dams actually form on Jefferson County housing stock, what a night leak needs, the insurance trap that follows, and what prevention is actually worth paying for.
Last reviewed July 20, 2026
The mechanism, not the basics
Ice dams don't start at the eave. They start at the ceiling.
The dam is just where the problem becomes visible. The cause is upstream, and it's the same cause on nearly every affected roof.
Heat rises out of the living space into the attic through the ceiling — around a hatch, a recessed light, a chimney chase, or simply through insulation sitting below today's code minimum. That heat warms the underside of the roof deck unevenly: the section over the heated attic runs warmer than the section over the cold overhang past the exterior wall line.
Snow sitting on the warm section melts. The meltwater runs downhill under the snowpack until it crosses onto the cold overhang, where the roof deck sits at outdoor temperature because no heat loss is reaching it from below. It refreezes there, at the eave, forming the dam.
Every storm after that adds more snow behind a dam that already exists. Meltwater has nowhere to go but backward, pooling on the roof surface behind the ice instead of running off the edge the way shingles and underlayment are built to shed it. Roofing sheds water moving downhill — it was never built to hold standing water uphill of an ice barrier, which is exactly what a dam creates. That's how a leak gets under the shingles, through the deck, and into the ceiling below: not through failed roofing, but through water sitting somewhere the roofing was never designed to keep out.
The number, and what it actually does
116.4 inches isn't a headline. It's how many times the cycle repeats.
116.4 in/yr
Watertown's snowfall normal is 116.4 inches a year — genuinely top-tier for the continental United States outside a handful of extreme Great Lakes snowbelt pockets.
Source: NOAA GHCN 1991–2020 Watertown normalsLast reviewed July 20, 2026
That total doesn't arrive in one storm. It arrives across repeated events over a full winter, and every event that lands on a roof already losing heat unevenly gets the same melt-refreeze treatment at the eave. More snow events in a season means more chances for the cycle to run — not necessarily a bigger single dam, but more openings to build one.
Age matters here as much as snowfall. Roughly 36% of Jefferson County's housing stock predates 1940, built to whatever attic-insulation standard existed at the time. Today's minimum is different: R-49 ceiling insulation, uniform across Climate Zones 4 through 8 under the 2025 ECCCNYS, effective December 31, 2025. A roof holding code-minimum insulation and a roof holding what a 1930s house shipped with are not the same roof in the same storm.
Source: 2025 ECCCNYS residential energy code, Table R402.1.2Last reviewed July 20, 2026
If it's happening right now
What to actually do the night a leak starts
A leak during an active melt isn't the moment to solve the roof. It's the moment to stop the damage and get the record straight.
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Move the water, not yourself
Get buckets, towels, and a tarp or plastic sheeting under the leak, and move anything valuable out from underneath it. Don't go up on an icy roof in the dark to look at anything — cold, ice, and a roof pitch are a bad combination even for someone who does this for a living.
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Relieve the load from the ground, if you can reach it
A roof rake used from the ground, on whatever section is safely reachable, removes some of the snow feeding the dam without anyone leaving the ground. Chipping or hacking at the ice itself — with anything, from a roof or a ladder — is how flashing and shingles get torn out from underneath, turning one leak into a bigger repair.
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Photograph it tonight
Interior stains, active drips, and anything visibly damaged, with a timestamp, before any cleanup starts. This becomes the record an insurance claim will need — more on that below.
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Call today or tomorrow, not for a promise of tonight
A same-day or next-day response from a licensed local roofer is a realistic ask during an active event. A company promising round-the-clock dispatch it can't actually staff is a bigger red flag than a phone that rings through until morning.
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Treat a same-night full-roof estimate with real skepticism
A legitimate emergency response is about stopping active water intrusion — a tarp, a temporary patch, sometimes careful ice removal. A full-replacement quote written in the dark, during a leak, before daylight or a real inspection, is the exact pattern homeowners are warned to distrust in door-to-door storm response.
The insurance trap
Why "ice dam" and "seepage" aren't the same claim
The mechanism above matters here too — how the water actually got in decides which policy language applies to it.
Standard homeowners' policies typically cover sudden and accidental water damage but exclude long-term seepage. Insurers evaluating an ice-dam claim don't always classify it as sudden damage from a specific storm — some classify the same physical damage as water intrusion, seepage, or a maintenance issue instead, which shifts it into the excluded category.
Source: The ice-dam insurance loopholeLast reviewed July 20, 2026
The distinction isn't cosmetic. The same water stain on the same ceiling can be a covered claim or a denied one — it depends entirely on which of those two descriptions ends up in the adjuster's file. That's exactly why the record built the night the leak starts carries real weight later.
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Photograph immediately, not eventually. Interior damage, dated, from the night it happens — not after cleanup, drying, or repair have already changed what an adjuster would see.
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Write down the timeline while it's fresh. The date, the weather conditions, and when the leak was first noticed — in your own words, in writing, the same day.
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Learn the two words that decide the claim. "Sudden and accidental" is the language that supports coverage. "Seepage," "gradual," and "maintenance-related" are the language that supports denial. A homeowner's own contemporaneous record is what keeps the first description in play.
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Keep a log of every claim conversation. Date, who you spoke with, and what was said — a habit that costs nothing and is often the only thing that survives a dispute.
Prevention, assessed honestly
What actually stops a dam from forming, and what just treats one after it has
The mechanism above points to the fix: remove the uneven heat loss, and there's no warm patch left for snow to melt against.
Air-sealing the attic floor — the hatch, top-plate penetrations, recessed lighting, chimney and plumbing chases — closes the specific paths that let heated air reach the roof deck unevenly. It addresses the actual cause identified above, not the symptom at the eave.
Insulation brought up to the current code minimum — R-49 uniformly across the region's climate zones under the 2025 ECCCNYS — reduces the residual heat loss that air-sealing alone doesn't catch. A roof built to a pre-1940 standard, or one that's simply settled and thinned over decades, is very often sitting well under that number without anyone having measured it.
Source: 2025 ECCCNYS Table R402.1.2Last reviewed July 20, 2026
Roof and ridge ventilation matters for the same reason: a vented attic that stays closer to outdoor temperature has less warm air reaching the deck to begin with, even before air-sealing and insulation are addressed.
None of the above is a roofing cost, and none of it should get quoted like one. Attic air-sealing and insulation retrofits price on a separate line from a roof replacement or repair — the same cost-driver questions are worth asking on the county roof cost guide.
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Heat cables treat the eave, not the cause. Electric de-icing cables melt a channel through ice that's already formed at the edge. They don't stop the heat loss that built the dam in the first place, and they only do that limited job if they're run every winter, in the right pattern, along the actual trouble spots — not installed once and forgotten.
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A cable left unmaintained is closer to decoration. A de-icing cable that isn't checked, positioned correctly, and run through the season doesn't meaningfully change what happens at the eave. It's worth real skepticism as a stand-alone fix, not a substitute for addressing heat loss.
Questions homeowners actually ask
Ice dam FAQ
Short answers first. The mechanics above are what makes them true.
What actually causes an ice dam?
Heat escapes from the living space into the attic and warms the roof deck unevenly — the section over the heated attic runs warmer than the section over the cold overhang past the exterior wall. Snow melts on the warm section, runs downhill under the snowpack, and refreezes the moment it crosses onto the cold section, building the dam. Every storm after that adds snow behind a dam that already exists, and the trapped meltwater backs up onto the roof instead of running off the edge the way the roofing was built to shed it.
Water is coming through my ceiling right now — what do I do?
Get buckets, towels, or a tarp under the leak and move anything valuable out from underneath it — don't go up on an icy roof to look at anything in the dark. A roof rake used from the ground can relieve some of the load feeding the dam without anyone leaving the ground. Photograph the interior damage, with a timestamp, before any cleanup starts. Then call a licensed local roofer for a same-day or next-day appointment. No real round-the-clock dispatch service exists in this market yet — a company that claims one does is worth a second look, not more confidence.
Will homeowners insurance cover ice dam damage?
It depends on how the damage gets classified, not just on what actually happened. Standard homeowners' policies typically cover sudden and accidental water damage but exclude long-term seepage. Insurers evaluating an ice-dam claim don't always classify it as sudden storm damage — some classify the same physical damage as water intrusion, seepage, or a maintenance issue instead, which moves it into the excluded category. A same-night, dated record of the damage is what supports the covered classification later.
Source: The ice-dam insurance loopholeLast reviewed July 20, 2026
Do heat cables actually stop ice dams?
They treat the eave, not the cause. Electric de-icing cables melt a channel through ice that has already formed; they don't stop the uneven heat loss that built the dam in the first place. They only do that limited job if they're run every winter, positioned correctly along the actual trouble spots — a cable installed once and left alone is closer to decoration than protection.
Is 116 inches of snow a year actually a lot?
Yes. Watertown's snowfall normal is 116.4 inches a year, genuinely top-tier for the continental United States outside a handful of extreme Great Lakes snowbelt pockets. That total doesn't arrive in one storm — it arrives across repeated events all winter, and every event that lands on a roof already losing heat unevenly gets the same melt-refreeze treatment at the eave.
Source: NOAA GHCN 1991–2020 Watertown snowfall normalsLast reviewed July 20, 2026
Should I climb up and try to remove the ice dam myself?
Not by chipping or hacking at it, and not by climbing an icy roof to do it. Both are how flashing and shingles get torn out from underneath, turning one leak into a bigger repair, and a roof pitch under ice is a fall risk even for someone who works on roofs for a living. A roof rake used from the ground, on whatever section is safely reachable, is the extent of the do-it-yourself response before calling a licensed local roofer.
From symptom to plan
If tonight's leak turned into "do I need a new roof," get a real answer.
Repair, replace, or just insulate — the right next step depends on what's actually happening under the shingles, not a phone-quote guess.
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