Ice dam risk in Lynbrook, NY

Will your roof get ice dams in Lynbrook, NY?

3.9 dam days a winter

Low risk. On an ordinary house in Lynbrook, conditions for an ice dam come on about 3.9 days in a normal winter, mostly in February and January.

Lynbrook averages 26 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 Lynbrook

Attic	Dam days	Risk
Air-sealed and well insulated	3.1	Low
Typical, some insulation, not air-sealed	3.9	Low
Older or poorly insulated, warm attic	4.9	Low

The attic matters less in Lynbrook than in colder towns: there are only 0.8 days a winter between a typical attic and a sealed one.

Preventing ice dams on a Lynbrook roof

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.

Lynbrook winter, month by month

Month	Snow (in)	Days on ground	Dam days
January	5.7	6.2	1.4
February	7.6	7.3	1.5
March	4.8	3.3	0.4
April	1.0	0.2	0.0
November	0.2	0.2	0.0
December	6.2	2.8	0.5

Lynbrook next to nearby towns

Lynbrook ranks 83 of 90 New York cities here for ice-dam days, behind Utica at 46.1 days.

East Rockaway, NY 1 mi, 3.9 days
Valley Stream, NY 2 mi, 3.7 days
Rockville Centre, NY 2 mi, 3.9 days
Hempstead, NY 4 mi, 3.9 days
Floral Park, NY 5 mi, 3.9 days

Where these numbers come from

NOAA 1991–2020 climate normals from Oceanside, 3.0 miles from Lynbrook. 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.