On Sunday, January 24, 2016 at 2:19:15 PM UTC-5, wrote:
My brother has 20" of snow on a 5/12 roof in Maryland, and rain has been forecasted for Tuesday.

Is the greatest danger from snow weight or from ice damming?

What would be the best strategy for the next 24 hours?

Thank you very much in advance.

Jutta Gibb

This is really cool - no pun intended.

Use a length of string or wire.

http://youtu.be/gEnJJeNHTLs