Please do not get up on your roof to shovel snow if you can avoid it
Two weekends ago was a snowy time and there were public service announcements urging homeowners to clear the snow off of their roofs. Every year as it gets snowier we see these ads and every year we at Eastern Maine Medical Center treat many people with fall injuries. This particular weekend we saw 20 people in the Emergency Room who fell off their roofs and 6 were admitted with serious injuries.
I am a surgeon and not a roofer or home builder. However, it should be said that most roofs in this area are built to withstand fairly large snow loads. the risk of a roof collapsing has to do with how much weight of snow has accumulated (ice and wet snow are heavier), how long the roof will need to support that extra weight (our roofs are meant to handle a large amount of weight for some time but not all year long), and what condition the roof and supports are in. After a large snow fall, some of the snow will slide off the roof, some will melt, and some will sublimate (when ice turns into vapor). Also, some roofs have a steeper pitch and will do better during the snowier times. Some roofs are in better condition or have been built more sturdily. If your house is old or you are concerned about the condition of your roof, it may be beneficial to have it looked at by a professional who can help guide you on this issue.
If you must clear your roof there are professionals that can be hired for the task. If you cannot get a professional, there are some tools that will help you clear off some of the snow load from the ground (roof rakes). Remember, the goal is not to completely clear the roof of snow. The goal is only to reduce the load to an amount that is less stressful on your roof. Therefore, you can leave the snow that is in the harder to reach areas.
If you must get up on the roof, there are fall arrest systems that can be bought and installed to protect you from serious injury. Obviously, these are easier to install before it becomes snowy. It is also recommended that you use non-slip boots or spikes to help prevent slips. If you are using a ladder, have a buddy present who can stabilize the ladder.
It is particularly dangerous for some people to risk falling. If you have heart or lung disease you are more likely to overexert yourself which could cause you to become dizzy and lose your balance. If you are taking blooding thinning medication you are at much more risk for serious bleeding complications from an injury. If you are one of these people, please seriously consider other ways to clear your roof than going up there yourself.