Ice dam risk in Portland, TN
Ice dams in Portland, TN: how often
0.1 dam days a winter
Almost never. An ordinary house in Portland sees 0.1 days a winter when an ice dam can form, because snow rarely stays on a roof long enough below freezing.
Portland averages 2 inches of snow a year and about 1 day with snow on the ground. Too little lies on the roof for long. The conditions that make a dam need all three at once: snow, cold at the eave and heat above it.
Do you need to do anything in Portland?
- Nothing for ice dams. If you are buying here and an inspector mentions water at the eaves, ask what they saw: it is far more likely a gutter, flashing or drip-edge problem than ice.
Snowy places are not always the worst: why snowfall misleads.
Portland winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 0.2 | 0.1 | 0.0 |
| February | 1.5 | 0.6 | 0.1 |
| March | 0.3 | 0.1 | 0.0 |
Portland next to nearby towns
Portland ranks 65 of 65 Tennessee cities here for ice-dam days, behind Crossville at 2.6 days.
- Franklin, KY 9 mi, 0.1 days
- White House, TN 12 mi, 0.6 days
- Gallatin, TN 15 mi, 0.8 days
- Springfield, TN 20 mi, 0.6 days
- Hendersonville, TN 21 mi, 0.1 days
Where these numbers come from
NOAA 1991–2020 climate normals from Portland Sewage Plt, 0.7 miles from Portland. 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.