Ice dam risk in Walla Walla, WA
Ice dams in Walla Walla, WA: how often
1.6 dam days a winter
Low risk. On an ordinary house in Walla Walla, conditions for an ice dam come on about 1.6 days in a normal winter, mostly in January and December.
Walla Walla averages 7 inches of snow a year and about 9 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 Walla Walla
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 1.0 | Very unlikely |
| Typical, some insulation, not air-sealed | 1.6 | Low |
| Older or poorly insulated, warm attic | 2.4 | Low |
The attic matters less in Walla Walla than in colder towns: there are only 0.6 days a winter between a typical attic and a sealed one.
What to do about ice dams in Walla Walla
- 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.
Walla Walla winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 1.0 | 3.1 | 0.6 |
| February | 2.2 | 2.0 | 0.3 |
| March | 0.2 | 0.3 | 0.0 |
| October | 0.1 | 0.0 | 0.0 |
| November | 0.3 | 1.1 | 0.1 |
| December | 2.7 | 2.6 | 0.6 |
Walla Walla next to nearby towns
Walla Walla ranks 14 of 91 Washington cities here for ice-dam days, behind Spokane at 13.0 days.
- Pendleton, OR 36 mi, 3.1 days
- Pasco, WA 40 mi, 0.3 days
- Kennewick, WA 41 mi, 0.3 days
- Richland, WA 48 mi, 0.3 days
- Hermiston, OR 48 mi, 2.6 days
Where these numbers come from
NOAA 1991–2020 climate normals from Walla Walla Regional Airport, 3.1 miles from Walla Walla. 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.