“An Ounce of Ice Dam Prevention = . . . . “
To an untrained eye, there are simply two spots on the roof that are snow-free.
To someone who knows about ice dams, though, there are two “hot spots” on the roof (missing insulation? directly above a Bathroom or shower?) where heat is escaping, causing snow to melt and (possibly) accumulate and re-freeze above the gutter.
When THAT happens, it’s called an “ice dam,” and the fix is much more expensive than simply adding insulation.
P.S.: a nice, even blanket of snow on a home’s roof acts as an insulating blanket, and (usually) indicates that the home’s attic is properly vented and insulated.