Ice dam risk in Morgantown, WV

Ice dams in Morgantown, WV: how often

6.0 dam days a winter

Moderate risk. On an ordinary house in Morgantown, conditions for an ice dam come on about 6.0 days in a normal winter, mostly in January and February.

Morgantown averages 14 inches of snow a year and about 25 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 Morgantown

Attic	Dam days	Risk
Air-sealed and well insulated	3.8	Low
Typical, some insulation, not air-sealed	6.0	Moderate
Older or poorly insulated, warm attic	8.8	Moderate

Sealing and insulating a typical attic takes out about 2.2 days a winter here. It drops the risk from moderate to low.

Preventing ice dams on a Morgantown 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.

Morgantown winter, month by month

Month	Snow (in)	Days on ground	Dam days
January	5.2	9.3	2.7
February	5.6	7.3	1.9
March	1.7	2.9	0.4
October	0.2	0.0	0.0
November	0.1	0.6	0.1
December	1.6	4.5	0.9

Morgantown next to nearby towns

Morgantown ranks 5 of 13 West Virginia cities here for ice-dam days, behind Weirton at 10.4 days.

Fairmont, WV 15 mi, 8.6 days
Clarksburg, WV 34 mi, 6.3 days
Washington, PA 40 mi, 11.6 days
Jefferson Hills, PA 46 mi, 6.0 days
Bethel Park, PA 48 mi, 11.6 days

Where these numbers come from

NOAA 1991–2020 climate normals from Lake Lynn, 7.5 miles from Morgantown. 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.

Snow-on-the-ground counts come from a second, nearby station, because the closest one does not record them.