Well don’t panic!
Ice damning is the process of snow melting from the upper part of your roof and re-freezing on the lower eaves as it cools. It cools because there is no heat below the eaves. As it re-freezes the ice flow backs up further up the roof. Now as new melting snow comes down the roof it really has no where to go because the ice dam blocks it. So the result is standing water on the roof. Standing water on the roof is always bad and will many times result in a leak. Ice/water shield is a product to help prevent this from happening. However, many older roofs have inadequate protection or no protection at all.
The quick solution? Call a professional to shovel your roof if possible. Or prevent it by installing commercial grade heating wires at the eaves of your home. See our list of best roofers around if you want someone to call. If you have questions just comment below and I will do my best to get back to you ASAP.