How Often Should Snow Be Cleared During a Large Storm

[Chris Messier]

I have read posts discussing who does the snow removal but didn't come across one regarding how often. Question is, if there was a snow storm that lasted let's say 8 hrs and accumulated10 inches, do you clean up once the storm stops or several times in between? With the concern of a slip and fall suit I wonder what the courts consider negligent. If you do it yourself, discount rent to a tenant, hire the neighborhood kid, or a property management company this should apply. If you rely on someone else for snow removal and they don't make it there until hours after the storm the landlord is ultimately responsible if someone falls on the stairs or walkways right?