Ice dam risk in Portales, NM
How often ice dams form in Portales
0.6 dam days a winter
Almost never. An ordinary house in Portales sees 0.6 days a winter when an ice dam can form, because snow rarely stays on a roof long enough below freezing.
Portales averages 8 inches of snow a year and about 3 days 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 Portales?
- 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.
Portales winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 1.7 | 1.2 | 0.3 |
| February | 1.4 | 0.6 | 0.1 |
| March | 0.7 | 0.2 | 0.0 |
| April | 0.2 | 0.0 | 0.0 |
| October | 0.3 | 0.2 | 0.0 |
| November | 0.5 | 0.3 | 0.0 |
| December | 2.8 | 0.7 | 0.1 |
Portales next to nearby towns
Portales ranks 10 of 19 New Mexico cities here for ice-dam days, behind Gallup at 6.1 days.
- Clovis, NM 20 mi, 2.1 days
- Levelland, TX 70 mi, 1.0 days
- Hereford, TX 70 mi, 2.5 days
- Lovington, NM 85 mi, 0.1 days
- Roswell, NM 87 mi, 1.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Portales, 0.3 miles from Portales. 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.