Ice dam risk in Pendleton, OR
Will your roof get ice dams in Pendleton, OR?
3.1 dam days a winter
Low risk. On an ordinary house in Pendleton, conditions for an ice dam come on about 3.1 days in a normal winter, mostly in December and January.
Pendleton averages 18 inches of snow a year and about 15 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 Pendleton
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 2.0 | Low |
| Typical, some insulation, not air-sealed | 3.1 | Low |
| Older or poorly insulated, warm attic | 4.5 | Low |
The attic matters less in Pendleton than in colder towns: there are only 1.1 days a winter between a typical attic and a sealed one.
Preventing ice dams on a Pendleton roof
- 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.
Pendleton winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 3.9 | 4.5 | 1.0 |
| February | 5.0 | 2.9 | 0.5 |
| March | 1.0 | 1.1 | 0.1 |
| November | 1.6 | 1.4 | 0.2 |
| December | 6.5 | 5.3 | 1.3 |
Pendleton next to nearby towns
Pendleton ranks 8 of 57 Oregon cities here for ice-dam days, behind Klamath Falls at 9.8 days.
- Hermiston, OR 25 mi, 2.6 days
- Walla Walla, WA 36 mi, 1.6 days
- Kennewick, WA 40 mi, 0.3 days
- La Grande, OR 43 mi, 6.1 days
- Pasco, WA 43 mi, 0.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Pendleton Wfo, 1.9 miles from Pendleton. 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.