Ice jams

Ice runs
River ice

Nature

Some rivers in the high latitudes of the northern hemisphere do not ice over completely in winter to form a stable ice cover, usually due to their high water velocities. Ice may be formed due to low temperatures, but it breaks away and large quantities move downstream, tending to damage bridge structures, producing ice jams and consequent flooding, particularly when such jams break. Ice moving in this way may causes much damage to hydroelectric installation intakes.

Incidence

Floods caused by ice jams and ice breaking up occur in the early spring. They often occur at constriction points such as at a sharp bend, gorge, bridge-crossing or any other physical obstacle. They may also occur where the gradient of a channel changes from steep to gentle, or at the point where a stream discharges into a lake. In Canada and Russia such floods typically occur when the ice and snow in the headwaters of northward flowing streams melt more rapidly than ice and snow in the lower reaches.

An analysis of the impact of climate warming on transportation in the MacKenzie Basin region of northern Canada found that there would be an increase of the open water (navigable) season on the MacKenzie River of 19-42 days, depending on the scenario used. This would favour an increase in shipping by barge, the least expensive method.

Claim

Ice jams are a dangerously underestimated threat that demands urgent attention. These blockages can cause catastrophic flooding, destroy infrastructure, and endanger entire communities in mere hours. Ignoring the risks of ice jams is reckless, as climate change increases their unpredictability and severity. We must prioritize research, monitoring, and prevention strategies now—before more lives and livelihoods are devastated by this preventable, yet all-too-often overlooked, natural disaster.

Counter-claim

Ice jams are vastly overblown as a problem. They are rare, localized events that affect only a handful of communities each year. Modern engineering and flood management have made their impact negligible. Compared to pressing global issues like climate change, poverty, or pandemics, worrying about ice jams is a waste of resources and attention. Let’s focus on real problems, not minor inconveniences that barely register on the scale of genuine threats.