Way back at the beginning, we blogged about the different kinds of flood. Maybe we should have included winter flooding from ice floes. Granted, it is a variety of fluvial (or riverine) flooding, but there are some unique characteristics to this type of flooding.
The best recent example of winter flooding has just receded in Brantford, Ontario reported in the Globe and Mail. The flooding is distinctive by the fact there is not necessarily an abnormal accumulation of water (though in this case it was unseasonable rain falling on snowpack). The flooding is a result of ice floes damming up a river and then releasing the built up water as the ice jams break apart. The result is a high-velocity flood event that deposits huge chunks of ice on and in property. It is also dangerously cold flood water.
The article mentions the flooding can be unpredictable, and that is true…kind of. While it is unpredictable when the flood will happen (like all floods), it is very predictable where the flooding is likely to go: lower elevations near the river. Good quality flood analytics can help underwriters assess this unusual flood risk, because the extents of the risk are essentially the same as fluvial flooding.
Like all floods, ice jam flooding is very dangerous. Maybe someone should mention that to this guy.