Ice dam risk in Grandview, WA

How often ice dams form in Grandview

5.5 dam days a winter

Moderate risk. On an ordinary house in Grandview, conditions for an ice dam come on about 5.5 days in a normal winter, mostly in January and December.

Grandview averages 10 inches of snow a year and about 20 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 Grandview

Attic	Dam days	Risk
Air-sealed and well insulated	3.5	Low
Typical, some insulation, not air-sealed	5.5	Moderate
Older or poorly insulated, warm attic	8.0	Moderate

Sealing and insulating a typical attic takes out about 2.0 days a winter here. It drops the risk from moderate to low.

What to do about ice dams in Grandview

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.

Grandview winter, month by month

Month	Snow (in)	Days on ground	Dam days
January	3.2	8.7	2.5
February	1.2	2.3	0.5
March	0.4	0.3	0.0
November	1.7	1.2	0.2
December	3.4	7.2	2.2

Grandview next to nearby towns

Grandview ranks 13 of 91 Washington cities here for ice-dam days, behind Spokane at 13.0 days.

Sunnyside, WA 7 mi, 5.5 days
West Richland, WA 25 mi, 0.3 days
Richland, WA 30 mi, 0.3 days
Kennewick, WA 35 mi, 0.3 days
Pasco, WA 38 mi, 0.3 days

Where these numbers come from

NOAA 1991–2020 climate normals from Moxee City 10 E, 21.8 miles from Grandview. 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.

The nearest weather station sits at a noticeably different elevation from Grandview, so the snow figures may run high or low for the town itself.