Ice dam risk in Valley Stream, NY
How often ice dams form in Valley Stream
3.7 dam days a winter
Low risk. On an ordinary house in Valley Stream, conditions for an ice dam come on about 3.7 days in a normal winter, mostly in February and January.
Valley Stream averages 26 inches of snow a year and about 20 days with snow on the ground. Most of it comes and goes within a few days. 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 Valley Stream
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 2.6 | Low |
| Typical, some insulation, not air-sealed | 3.7 | Low |
| Older or poorly insulated, warm attic | 5.0 | Moderate |
The attic matters less in Valley Stream than in colder towns: there are only 1.1 days a winter between a typical attic and a sealed one.
Preventing ice dams on a Valley Stream roof
- Check the gutters before the first snow and clear them, so meltwater has somewhere to go. If you see icicles thicker than a finger along the eave after a storm, that is the early sign to look at the attic.
Snowy places are not always the worst: why snowfall misleads.
Valley Stream winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 7.5 | 6.2 | 1.4 |
| February | 8.6 | 7.3 | 1.5 |
| March | 4.3 | 3.3 | 0.3 |
| April | 0.6 | 0.2 | 0.0 |
| November | 0.4 | 0.2 | 0.0 |
| December | 4.5 | 2.8 | 0.4 |
Valley Stream next to nearby towns
Valley Stream ranks 89 of 90 New York cities here for ice-dam days, behind Utica at 46.1 days.
- Lynbrook, NY 2 mi, 3.9 days
- East Rockaway, NY 2 mi, 3.9 days
- Rockville Centre, NY 4 mi, 3.9 days
- Floral Park, NY 4 mi, 3.9 days
- New Hyde Park, NY 5 mi, 3.9 days
Where these numbers come from
NOAA 1991–2020 climate normals from Jfk International Airport, 3.6 miles from Valley Stream. 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.