So we're about get a lot of snow. Is this something to be concerned about? How do you know when your roof has too much snow on it?
First and foremost, your house is probably designed to withstand excessive amounts of snow. As long as your house meets building code, you should be fine in most conditions.
However, if you want to be sure, lets examine a few factors. The wetness of the snow makes a big difference as to it's weight. In fact, 6 inches of wet snow is equal to about 38 inches of dry snow. So when checking the forecast, pay attention to the wetness of the snow and also consider if the amount of snow is extreme for your area. If it's not extreme, your house is probably built to code and the code will take into account historical snow falls.
This theory is great but it's often hard to gauge how wet the snow is and/or how the snowfall compares to other snowfalls historically. If you want to be certain that the amount of snow on your roof is okay, see if the interior doors in your house begin to stick. Too much weight on the roof can shift the framing causing the interior doors to stick (ignore the exterior doors). Keep in mind, houses that have had their interior load bearing walls improperly removed are the most susceptible to roof collapses.
What to do
Keep in mind that many people have serious and fatal accidents while on ladders every year even without snow and ice. So, proceed with the utmost caution or hire a professional crew with the correct equipment to do the job for you.
If your house is only one story, you may be able to remove the snow yourself using a long handled snow rake. You can pick these up at a local hardware store and they shouldn't run you more than $50.
Check out this video of an effective snow removal tool!