Ice dam risk in New Carrollton, MD
Ice dams in New Carrollton, MD: how often
2.9 dam days a winter
Low risk. On an ordinary house in New Carrollton, conditions for an ice dam come on about 2.9 days in a normal winter, mostly in February and January.
New Carrollton averages 16 inches of snow a year and about 14 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 New Carrollton
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 2.3 | Low |
| Typical, some insulation, not air-sealed | 2.9 | Low |
| Older or poorly insulated, warm attic | 3.7 | Low |
The attic matters less in New Carrollton than in colder towns: there are only 0.6 days a winter between a typical attic and a sealed one.
Preventing ice dams on a New Carrollton 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.
New Carrollton winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 5.7 | 4.5 | 1.1 |
| February | 5.0 | 5.5 | 1.2 |
| March | 2.5 | 2.2 | 0.3 |
| April | 0.1 | 0.0 | 0.0 |
| November | 0.2 | 0.1 | 0.0 |
| December | 2.3 | 2.1 | 0.4 |
New Carrollton next to nearby towns
New Carrollton ranks 15 of 23 Maryland cities here for ice-dam days, behind Hagerstown at 12.1 days.
- Greenbelt, MD 2 mi, 2.9 days
- College Park, MD 4 mi, 2.9 days
- Hyattsville, MD 4 mi, 2.1 days
- Takoma Park, MD 7 mi, 2.1 days
- Bowie, MD 7 mi, 3.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from Beltsville, 5.3 miles from New Carrollton. 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.