Ice dam risk in Batavia, NY
How often ice dams form in Batavia
19.5 dam days a winter
High risk. On an ordinary house in Batavia, conditions for an ice dam come on about 19.5 days in a normal winter, mostly in January and February.
Batavia averages 74 inches of snow a year and about 66 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 Batavia
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 10.0 | Moderate |
| Typical, some insulation, not air-sealed | 19.5 | High |
| Older or poorly insulated, warm attic | 31.3 | High |
Sealing and insulating a typical attic takes out about 9.5 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 31.3 days.
Preventing ice dams on a Batavia roof
- 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.
Batavia winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 23.0 | 19.3 | 6.8 |
| February | 18.6 | 17.3 | 5.8 |
| March | 11.4 | 11.5 | 2.7 |
| April | 1.7 | 1.0 | 0.1 |
| October | 0.4 | 0.0 | 0.0 |
| November | 5.8 | 3.5 | 0.5 |
| December | 13.0 | 13.1 | 3.7 |
Batavia next to nearby towns
Batavia ranks 38 of 90 New York cities here for ice-dam days, behind Utica at 46.1 days.
- Lancaster, NY 26 mi, 21.2 days
- Depew, NY 27 mi, 21.2 days
- Lockport, NY 29 mi, 21.4 days
- Rochester, NY 31 mi, 21.2 days
- Kenmore, NY 35 mi, 21.4 days
Where these numbers come from
NOAA 1991–2020 climate normals from Batavia, 2.2 miles from Batavia. 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.
- Snow-on-the-ground counts come from a second, nearby station, because the closest one does not record them.