Ice dam risk in Wenatchee, WA
Ice dams in Wenatchee, WA: how often
7.6 dam days a winter
Moderate risk. On an ordinary house in Wenatchee, conditions for an ice dam come on about 7.6 days in a normal winter, mostly in January and December.
Wenatchee averages 17 inches of snow a year and about 30 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 Wenatchee
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 4.9 | Low |
| Typical, some insulation, not air-sealed | 7.6 | Moderate |
| Older or poorly insulated, warm attic | 11.0 | Moderate |
Sealing and insulating a typical attic takes out about 2.7 days a winter here. It drops the risk from moderate to low. An older house with a warm attic should expect closer to 11.0 days.
Preventing ice dams on a Wenatchee roof
- 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.
Which to spend on first: air sealing or heat cable.
Wenatchee winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 5.6 | 12.7 | 3.5 |
| February | 3.0 | 4.8 | 1.0 |
| March | 0.4 | 1.0 | 0.1 |
| November | 1.5 | 1.4 | 0.2 |
| December | 6.0 | 10.0 | 2.7 |
Wenatchee next to nearby towns
Wenatchee ranks 7 of 91 Washington cities here for ice-dam days, behind Spokane at 13.0 days.
- East Wenatchee, WA 2 mi, 7.6 days
- Ellensburg, WA 32 mi, 6.9 days
- Moses Lake, WA 54 mi, 6.7 days
- Yakima, WA 59 mi, 6.9 days
- Snoqualmie, WA 72 mi, 0.2 days
Where these numbers come from
NOAA 1991–2020 climate normals from Wenatchee, 1.0 miles from Wenatchee. 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.