On 1/12/2020 10:44 AM, Curious sound wrote:
During a recent rain, that turned to ice and then snow In Kansas City, our
attic rotating vent on top of the roof formed icicles that are spinning
around
as the vent spins. It is making a loud thumping sound with each rotation,
approx every two seconds.
How do I stop the icicles from forming in the future? How do I knock them
down? Should I be concerned about it causing damage to the roof?

Perhaps the vanes on the vent have become corroded and make a good site
for ice crystals to adhere to the surface, or your attic (I assume it is
an unfinished crawl space) is too warm and/or humid due to inadequate
insulation on the floor of the attic or inadequate outside air
circulation within the attic due to inadequate, blocked, or mis-located
passive vents? If the rotating vent is corroded, replace it. If not,
when the weather warms up, silicon spray may discourage near-term ice
build-up but the spray will need to be re-applied periodically. If your
attic is not properly insulated and ventilated, you may be losing a lot
of heat in the winter (and transmitting a lot of heat into the house
during the summer) through the ceiling immediately below the attic.
Adding insulation pays for itself in saved energy costs rather quickly
unless you're planning to move in the very near future. Or, you could
have experienced a particularly severe ice storm that coated most
exposed surfaces. And, if you've had problems with ice dams near the
edge of your roof, it's a sure sign of insulation/venting problems.

The icicles can't be that large if they still allow the vent to spin.
Therefore, they can't be heavy enough to damage your roof. From what I
see on-line, the temperature today in KC should be in the mid-high 30s
and sunny. By evening, they should be substantially melted. Good luck!