Ice dam risk in Mount Vernon, WA
How often ice dams form in Mount Vernon
0.3 dam days a winter
Almost never. An ordinary house in Mount Vernon sees 0.3 days a winter when an ice dam can form, because snow rarely stays on a roof long enough below freezing.
Mount Vernon 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 Mount Vernon?
- 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.
Mount Vernon winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 0.6 | 1.6 | 0.2 |
| February | 0.2 | 0.0 | 0.0 |
| March | 0.4 | 0.1 | 0.0 |
| October | 0.1 | 0.0 | 0.0 |
| November | 0.7 | 0.8 | 0.0 |
| December | 3.7 | 1.4 | 0.1 |
Mount Vernon next to nearby towns
Mount Vernon ranks 32 of 91 Washington cities here for ice-dam days, behind Spokane at 13.0 days.
- Burlington, WA 3 mi, 0.3 days
- Sedro-Woolley, WA 7 mi, 0.3 days
- Anacortes, WA 15 mi, 0.2 days
- Oak Harbor, WA 17 mi, 0.2 days
- Arlington, WA 19 mi, 0.4 days
Where these numbers come from
NOAA 1991–2020 climate normals from Sedro-Woolley, 6.5 miles from Mount Vernon. 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.