Illinois River in western La Salle County under flood advisory

For those of us shivering, Monday will bring relief. Temperatures will climb above freezing and stay there the rest of the week. But with the warming spell comes a downside: a risk of flooding.

The National Weather Service issued a flood advisory Thursday, calling for minor flooding on the Illinois River from the Starved Rock Lock and Dam to the confluence of Big Bureau Creek.

While we are expecting temperatures to warm up, we’re expecting a gradual warmup, and we’re not expecting major flooding.”

—  David King, meteorologist with the National Weather Service in Romeoville

For now, the NWS expects only minor flooding Sunday and again Wednesday, with no early indicators of a major flood event.

“As of right now, the ongoing flooding is just due to the heavier river ice and ice jams,” said David King, a meteorologist with the NWS office in Romeoville. “While we are expecting temperatures to warm up, we’re expecting a gradual warmup, and we’re not expecting major flooding.

“We would need temperatures much higher above freezing for there to be heavy melting.”

Nevertheless, Utica Mayor David Stewart is among those waiting to see whether the flood projections are adjusted – something that’s happened in recent years with little warning.

“At this time, the trends appear to be OK from a village perspective,” Stewart said. “We will continue monitoring and, if needed, the village will send out any communications to its residents and businesses.”

Stewart has good reason to keep an eye peeled.

At one point the Illinois River would rise slowly, and Utica had days to prepare for a flood, but that is no longer the case. Suburban sprawl has altered the watershed, and the river is prone to more abrupt changes.

Notably, eight of the 20 worst floods on record (dating back to 1869) have occurred since 2000. The Illinois Valley most recently had near-misses in 2015 – about 30 feet above flood stage twice that year – but endued major flooding in 2008, 2009 and 2013.

The latter remains the all-time high at 34.44 feet above flood stage.