Ice dam risk in Lake Oswego, OR
How often ice dams form in Lake Oswego
0.1 dam days a winter
Almost never. An ordinary house in Lake Oswego sees 0.1 days a winter when an ice dam can form, because snow rarely stays on a roof long enough below freezing.
Lake Oswego averages 4 inches of snow a year and about 2 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 Lake Oswego?
- 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.
Lake Oswego winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 1.3 | 0.6 | 0.0 |
| February | 1.4 | 0.7 | 0.0 |
| December | 0.9 | 0.3 | 0.0 |
Lake Oswego next to nearby towns
Lake Oswego ranks 30 of 57 Oregon cities here for ice-dam days, behind Klamath Falls at 9.8 days.
- Tigard, OR 4 mi, 0.1 days
- West Linn, OR 4 mi, 0.1 days
- Milwaukie, OR 4 mi, 0.1 days
- Tualatin, OR 4 mi, 0.0 days
- Gladstone, OR 6 mi, 0.1 days
Where these numbers come from
NOAA 1991–2020 climate normals from Portland Kgw-Tv, 7.2 miles from Lake Oswego. 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.