The glaciers in Alaska lead to water and are always calving. I don't think that raises the water levels as the towns are all along the water way. I have watched the calving and it goes on continually. been on two cruises but there are no floods of the towns...
Some of the breaking off is as big as a house or bus and you can hear the glacier booming all day...(Side note) the natives call it white thunder and it sounds like thunder as they crack and then fall... Of course if it all melted at once there would be floods until the water reaches its level but the waterways all lead to the ocean. When dealing with a body of water as big as the Pacific Ocean, is it possible to actually raise the level of the Ocean more than a few inches...
Nearly all of the icecap at the south pole sits on land, and it is miles thick. A lot of ice (but not all) at the north pole also sits on land, and that is very thick, as well.
If it were all to melt into the oceans at once, it would have an effect on sea levels, but by how much is anybody's guess.
The reason those towns near the glacier calving don't become swamped, is because as big as those chunks of ice are, they're infinitesimally small, compared to the volume of the ocean water they're falling into. The amount they raise the sea level isn't even measurable.
Here’s what I found on a search from one of the first sites that came up. Seems to sound about right from other things I recall:
The main ice covered landmass is Antarctica at the South Pole, with about 90 percent of the world’s ice (and 70 percent of its fresh water). Antarctica is covered with ice an average of 2,133 meters (7,000 feet) thick. If all of the Antarctic ice melted, sea levels around the world would rise about 61 meters (200 feet). But the average temperature in Antarctica is -37°C, so the ice there is in no danger of melting. In fact in most parts of the continent it never gets above freezing.
At the other end of the world, the North Pole, the ice is not nearly as thick as at the South Pole. The ice floats on the Arctic Ocean. If it melted sea levels would not be affected.
There is a significant amount of ice covering Greenland, which would add another 7 meters (20 feet) to the oceans if it melted. Because Greenland is closer to the equator than Antarctica, the temperatures there are higher, so the ice is more likely to melt.
But there might be a less dramatic reason than polar ice melting for the higher ocean level — the higher temperature of the water. Water is most dense at 4 degrees Celsius. Above and below this temperature, the density of water decreases (the same weight of water occupies a bigger space). So as the overall temperature of the water increases it naturally expands a little bit making the oceans rise.