One of the dangers involved with wintertime snow is when it slides off of a roof and comes crashing down. If this mix of ice and snow was to fall down on someone passing by below, it could seriously hurt, or even kill them. While cleaning off your roof regularly will be helpful to prevent this, for many homeowners, this might not be feasible.
One solution to this problem is to install snow guards. Snow guards are placed at the bottom of your roof and work by breaking up the snow and ice sheets so that they don’t all slide off at once. They should, however, not be installed on any extended parts of the roof, since this might add too much extra weight to a part of the roof that isn’t as well supported.
You won’t usually find snow guards installed on your home unless a previous owner decided to install them, but it is not very complicated or expensive.