Ice dam risk in Des Moines, WA
Ice dams in Des Moines, WA: how often
0.2 dam days a winter
Almost never. An ordinary house in Des Moines sees 0.2 days a winter when an ice dam can form, because snow rarely stays on a roof long enough below freezing.
Des Moines averages 6 inches of snow a year and about 4 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 Des Moines?
- 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.
Des Moines winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 1.8 | 0.9 | 0.1 |
| February | 2.2 | 1.1 | 0.1 |
| March | 0.4 | 0.2 | 0.0 |
| November | 0.2 | 0.3 | 0.0 |
| December | 1.7 | 1.3 | 0.1 |
Des Moines next to nearby towns
Des Moines ranks 53 of 91 Washington cities here for ice-dam days, behind Spokane at 13.0 days.
- SeaTac, WA 4 mi, 0.2 days
- Kent, WA 5 mi, 0.2 days
- Federal Way, WA 5 mi, 0.2 days
- Burien, WA 6 mi, 0.2 days
- Tukwila, WA 6 mi, 0.2 days
Where these numbers come from
NOAA 1991–2020 climate normals from Seattle Tacoma Airport, 3.9 miles from Des Moines. 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.