Every year during a thaw my downspout freezes. It's on the north side of the building so it's shaded during the day and presently frozen solid. The thawing snow on the 1,400 square foot graded roof melts and rushes to the gutter where it drops into the downspout.
Five years ago this wasn't a problem since my original copper downspout looked like this:

The above is a photo of my neighbors down spout.
Four years ago I had contracted to have the
gutter and only the gutter replaced. The price was 100.00.
Wilken's crew arrived, I left for the morning, and when I returned home I found two men on the roof and the copper downspout
in the yard. They replaced it with an aluminum downspout with an elbow that catches thawing snow and causes it to freeze at the joint creating a dam. They also neglected to replace the gutter on the side of my building and did not install fascia under the 20 foot gutter. Idjets.
Less than a year later I was in small claims court with the owner Paul Wilken of Wilken Seamless Guttering and his two 'witnesses' -- his employees who stole my downspout and sold it for scrap. My beautiful and historic original downspout! They told the judge they scraped it for 140.00.
Paul argued he couldn't attach aluminum to copper. I agreed and mentioned I was aware of galvanic action but that a piece could have been used to prevent the metals from meeting and
removing the downspout had never been discussed.
I won the case but only the 100.00 I originally paid. The original downspout had been anchored into the brick. These chumps drilled into the
mortar and the freezing water is popping out mortar joints. Oh yeah, I also have gaping holes in brick.
Yep, that's a lit candle under the joint. Talk about hooiser rehabbing!
I took this photo yesterday and the ice was gone within an hour.
What worked best was pots of boiling water slowly poured onto the metal from
both floors.

The ice along the outside of the downspout is a result of thawing snow dripping from the above gutter. Had I not found a way to melt the ice on the inside and outside there would have been more water damage inside the house. Yes, it did cause damage to an interior wall.


Mortar joint popping out from ice: