When doing any form of roof work it is important to use safety precautions. The more steep the pitch of the roof the more precautions that need to be taken. Use this “pitch finder tool” to find the pitch of your roof.
Based on OSHA standards there are a handful of rules that must be followed based on the height of the roof from the ground, the pitch of the roof, and a few other specifications. See Cal OSHA roofing standards for more info.