Why can newly calved icebergs remain trapped inside fjords?

Newly calved icebergs can remain trapped inside their fjords of origin for long periods if their draft—the depth of the submerged portion of the iceberg—exceeds the water depth of the submerged sill located at the mouth of the fjord.1

Additionally, in narrower fjords, icebergs may face further challenges in moving seaward due to specific circulation patterns. These fjords often experience an estuarine circulation where outward flow at the surface is nearly balanced by an inward flow at depth. Because an iceberg’s draft allows it to feel both of these opposing currents, it does not move toward the open ocean as readily as sea ice does.2