Ice dam risk in Fairmont, WV
Ice dams in Fairmont, WV: how often
8.6 dam days a winter
Moderate risk. On an ordinary house in Fairmont, conditions for an ice dam come on about 8.6 days in a normal winter, mostly in January and February.
Fairmont averages 26 inches of snow a year and about 32 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 Fairmont
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 5.2 | Moderate |
| Typical, some insulation, not air-sealed | 8.6 | Moderate |
| Older or poorly insulated, warm attic | 12.8 | Moderate |
Sealing and insulating a typical attic takes out about 3.4 days a winter here. It does not move the risk band, but it shortens every dam. An older house with a warm attic should expect closer to 12.8 days.
What to do about ice dams in Fairmont
- 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.
Which to spend on first: air sealing or heat cable.
Fairmont winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 9.7 | 13.1 | 3.9 |
| February | 7.7 | 9.9 | 2.8 |
| March | 3.3 | 3.0 | 0.5 |
| April | 0.2 | 0.2 | 0.0 |
| October | 0.1 | 0.0 | 0.0 |
| November | 0.9 | 0.6 | 0.1 |
| December | 3.6 | 5.3 | 1.3 |
Fairmont next to nearby towns
Fairmont ranks 2 of 13 West Virginia cities here for ice-dam days, behind Weirton at 10.4 days.
- Morgantown, WV 15 mi, 6.0 days
- Clarksburg, WV 18 mi, 6.3 days
- Washington, PA 48 mi, 11.6 days
- Wheeling, WV 50 mi, 4.4 days
- Jefferson Hills, PA 58 mi, 6.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from Tygart Dam, 13.0 miles from Fairmont. 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.