Warming trend sparks “Ice Jam” flood warnings across Southern Indiana

INDIANA — After a frigid stretch that saw some of the deepest snowpack in over a decade, southern Indiana residents are being warned to keep a close eye on local waterways. As temperatures climb this week, emergency management departments are sounding the alarm over the risk of ice jams and flash flooding.

According to emergency officials, the thick blanket of snow currently on the ground holds a significant “water equivalent”—roughly 0.5 to 1.5 inches of liquid water per square foot. As this snow melts and flows into rivers already choked with ice, the risk of structural “jams” increases significantly.

An ice jam occurs when rising water levels break up frozen river surfaces into large chunks. These chunks then float downstream until they encounter an obstacle—such as a bridge pier, a narrow channel, or a sharp bend in the river.

When these chunks pile up, they act as a temporary dam. Water can back up rapidly behind the jam, flooding upstream areas, while a sudden “release” of the jam can send a wall of water and ice crashing into communities downstream.

Officials are asking residents near rivers and streams to be vigilant for the following signs of trouble:

• Look for large sheets of ice cracking or moving as a single mass.
• A sudden drop in downstream water levels (indicating a jam has formed upstream) or a rapid rise in water levels in low-lying areas.
• Loud “grinding” or “popping” noises coming from the river as ice sheets collide.

The risk is heightened by the upcoming weather pattern. While the initial melt is driven by the sun and warmer air, a predicted rainfall late next week could act as a catalyst, rapidly increasing the volume of runoff and the speed of the ice breakup.

Warming temperatures will send that snowmelt into local waterways that are just starting to thaw, officials noted. This speeds up the breakup and increases the likelihood of ice piling up in bends of the stream.

Residents are urged never to walk on thinning river ice and to keep children and pets away from the banks of rising streams.

If you observe a significant buildup of ice or see water beginning to crest over banks near a suspected jam, you should report it immediately. Call 911 if there is an immediate threat to life or property. Contact your local County Emergency Management Agency (EMA) or the non-emergency dispatch line for your area.