Have you ever heard of the “ice tsunami”? This natural phenomenon, as impressive as it is destructive, threatens cold regions. Unlike its aquatic cousin which breaks in a few minutes, it advances slowly but can cause considerable damage to coastal infrastructure. And to remember that nature remains unpredictable even in its slowest manifestations.
Also known as ice jam or ice heave, this phenomenon mainly manifests itself at the end of winter and the beginning of spring. During periods of mild weather, the surface ice layer begins to partially melt, creating spaces between the ice blocks. Under the influence of strong winds and storms, these pieces of ice are pushed towards the coasts, gradually forming a destructive wall.
Devastating consequences
In 1884, Montreal experienced one of the most memorable ice tsunamis, immortalized in period photographs that show spectacular piles of ice in the city’s streets.
Ice accumulation can reach impressive proportions, rising up to ten meters in height – the equivalent of a three-story house – and extending over several hundred meters. The potential damage is considerable: bridges washed away, buildings damaged and ground scraped by the inexorable progression of the ice.
The most affected regions are mainly the polar zones, particularly the coasts of Alaska, where violent winds are frequent. However, the phenomenon can also affect more temperate regions: the great lakes of North America and even certain Alpine lakes can be the scene of these spectacular events.
What to do in the face of an ice tsunami?
Faced with this winter threat, authorities and scientists have developed several prevention strategies:
- preventive weakening of ice by cutting into blocks or drilling
- spreading heat absorbing materials to promote gradual melting
- the use of icebreakers and hovercraft to create flow channels
- the establishment of monitoring and early warning systems
Particularly exposed coastal communities have also adapted their infrastructure, by building special sea walls and reinforcing the foundations of buildings located in risk areas.
Scientists are concerned about the impact of global warming on the frequency and intensity of ice tsunamis. More sudden and more frequent temperature variations could increase the risk of ice jams, particularly in Arctic regions where warming is more marked.
- The ice tsunami is a winter phenomenon that occurs during periods of thaw, which can form walls of ice more than 10 meters high
- The polar regions are the most affected, but the phenomenon can occur anywhere where water freezes in winter
- Prevention techniques exist, but climate change could amplify the phenomenon in the years to come
