Ice dam risk in Havre de Grace, MD
Will your roof get ice dams in Havre de Grace, MD?
3.4 dam days a winter
Low risk. On an ordinary house in Havre de Grace, conditions for an ice dam come on about 3.4 days in a normal winter, mostly in February and January.
Havre de Grace averages 18 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 Havre de Grace
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 2.6 | Low |
| Typical, some insulation, not air-sealed | 3.4 | Low |
| Older or poorly insulated, warm attic | 4.4 | Low |
The attic matters less in Havre de Grace than in colder towns: there are only 0.8 days a winter between a typical attic and a sealed one.
What to do about ice dams in Havre de Grace
- 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.
Havre de Grace winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 5.0 | 4.7 | 1.3 |
| February | 7.1 | 5.0 | 1.3 |
| March | 2.6 | 2.1 | 0.3 |
| April | 0.1 | 0.0 | 0.0 |
| November | 0.3 | 0.1 | 0.0 |
| December | 3.0 | 2.2 | 0.5 |
Havre de Grace next to nearby towns
Havre de Grace ranks 8 of 23 Maryland cities here for ice-dam days, behind Hagerstown at 12.1 days.
- Aberdeen, MD 4 mi, 3.4 days
- Bel Air, MD 12 mi, 3.4 days
- Elkton, MD 16 mi, 3.5 days
- Newark, DE 21 mi, 3.5 days
- Middletown, DE 22 mi, 3.5 days
Where these numbers come from
NOAA 1991–2020 climate normals from Octoraro Lake, 17.6 miles from Havre de Grace. 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.