Ice dam risk in Amsterdam, NY
Will your roof get ice dams in Amsterdam, NY?
24.7 dam days a winter
High risk. On an ordinary house in Amsterdam, conditions for an ice dam come on about 24.7 days in a normal winter, mostly in January and February.
Amsterdam averages 64 inches of snow a year and about 84 days with snow on the ground. Snow that lies that long is what turns a little attic heat into a ridge of ice at the eave. The conditions that make a dam need all three at once: snow, cold at the eave and heat above it.
What your attic does to that number in Amsterdam
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 14.1 | Moderate |
| Typical, some insulation, not air-sealed | 24.7 | High |
| Older or poorly insulated, warm attic | 37.8 | Severe |
Sealing and insulating a typical attic takes out about 10.5 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 37.8 days.
What to do about ice dams in Amsterdam
- Air-seal the attic floor: the gaps around the hatch, light fixtures, plumbing stacks and the top plates of interior walls. This is the fix that removes the cause, and it usually costs less than a season of contractor ice removal.
- Rake the bottom three or four feet of roof after any storm that leaves more than about six inches, from the ground with a roof rake.
- At the next reroof, ask for ice-and-water membrane under the shingles from the eave to at least 24 inches inside the wall line. It does not stop a dam; it stops the leak when one forms.
Which to spend on first: air sealing or heat cable.
Amsterdam winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 16.5 | 23.1 | 8.2 |
| February | 15.7 | 23.0 | 7.4 |
| March | 11.4 | 16.7 | 3.7 |
| April | 1.8 | 1.8 | 0.2 |
| October | 0.1 | 0.1 | 0.0 |
| November | 2.9 | 3.2 | 0.5 |
| December | 15.1 | 16.2 | 4.7 |
Amsterdam next to nearby towns
Amsterdam ranks 19 of 90 New York cities here for ice-dam days, behind Utica at 46.1 days.
- Gloversville, NY 11 mi, 24.7 days
- Schenectady, NY 16 mi, 17.0 days
- Saratoga Springs, NY 23 mi, 24.7 days
- Cohoes, NY 27 mi, 17.0 days
- Albany, NY 28 mi, 17.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from Saratoga Springs 4 SW, 19.9 miles from Amsterdam. A dam day is a day with snow on the roof and freezing at the eave while heat or sun melts the snow above it. This describes a normal winter, not this one.