Ice dam risk in Winchester, VA
Ice dams in Winchester, VA: how often
4.7 dam days a winter
Low risk. On an ordinary house in Winchester, conditions for an ice dam come on about 4.7 days in a normal winter, mostly in February and January.
Winchester averages 23 inches of snow a year and about 22 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 Winchester
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 3.5 | Low |
| Typical, some insulation, not air-sealed | 4.7 | Low |
| Older or poorly insulated, warm attic | 6.3 | Moderate |
The attic matters less in Winchester than in colder towns: there are only 1.2 days a winter between a typical attic and a sealed one.
What to do about ice dams in Winchester
- 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.
Winchester winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 6.9 | 6.7 | 1.7 |
| February | 8.0 | 7.2 | 1.6 |
| March | 3.8 | 2.5 | 0.4 |
| November | 0.6 | 0.3 | 0.0 |
| December | 3.8 | 4.8 | 1.0 |
Winchester next to nearby towns
Winchester ranks 1 of 39 Virginia cities here for ice-dam days, the worst in the state.
- Front Royal, VA 17 mi, 3.6 days
- Martinsburg, WV 22 mi, 4.7 days
- Leesburg, VA 33 mi, 2.8 days
- Warrenton, VA 38 mi, 4.5 days
- Hagerstown, MD 40 mi, 12.1 days
Where these numbers come from
NOAA 1991–2020 climate normals from Winchester, 1.6 miles from Winchester. 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.